Patients with a positive HCG due to tumor secretion may be permitted to enroll if lack of pregnancy can be documented (e.g. transvaginal ultrasound or serial HCG) and with approval by the Protocol chair. - WOCBP must agree to follow instructions for method(s) of contraception from the time of enrollment for the duration of treatment with study drug(s) plus 5 half-lives of study drug(s) plus 4 weeks (duration of ovulatory cycle) for a total of 5 months post t reatment completion. - Men who are sexually active with WOCBP must agree to follow instructions for method(s) of contraception for the duration of treatment with study drug(s) plus 5 half -lives of study drug(s) plus 90 days (duration of sperm turnover) for a total of 7 months post-treatment completion. - At least one barrier method of contraception must be employed by all sexually active patients (male and female), regardless of other methods , to prevent the transfer of body fluids . 3.1.11 Ability to understand and willingness to sign a written informed consent document. 3.2 Exclusion Criteria 3.2.1 Patient has a known history or evidence of brain metastases . 3.2.2 Patient who has had chemotherapy, radiation , or biological cancer therapy within 14 days prior to the first dose of study drug . 3.2.3 Patient has received an investigational agent or us ed an investigational device within 28 days of the first dose of study drug . 3.2.4 Patient is expected to require any other form of systemic or localized antineoplastic therapy while on study. 3.2.5 Patients who have had surgery within 28 days of dosing of investigational agent, excluding minor procedures (dental work, skin biopsy, etc .), celiac plexus block, and biliary stent placement . 3.2.6 Patients who have received any prophylactic vaccine within 14 days of first dose of study drug (7 days for the COVID vaccine) or received a live vaccine within 30 days of planned start of study therapy. 3.2.7 Patients with a history of prior treatment with anti-PD-1, anti -PD-L1, anti -PD-L2, anti-CTLA4 antibodies . 3.2.8 Have used any systemic steroids within 14 days of study treatment . J1790 / Version 7.0/ December 10, 2020 14 3.2.9 Use more than 2 g/day of acetaminophen . 3.2.1 0 Patients on immunosuppressive agents (e.g., TNF pathway inhibitors, PI3 kinase inhibitors) within 7 days of study treatment . 3.2.1 1 Patients receiving g rowth factors including, but not limited to, granulocyte -colony stimulating factor (G -CSF), GM -CSF, erythropoietin, within 14 days of study drug administration. Use of such agents while on study is also prohibited. 3.2.12 Patient has a known allergy to b oth penicillin and sulfa . 3.2.13 History of severe hypersensitivity reaction to any monoclonal antibody. 3.2.14 Patient has a known or suspected hypersensitivity to GM -CSF, hetastarch, corn, dimethyl sulfoxide, fetal bovine serum, trypsin (porcine origi n), yeast or any other component of GVAX pancreas vaccine or CRS -207 (e.g., glycerol) . 3.2.15 Have current or prior history of infection or clinically significant adverse events (AEs) associated with an exogenous implant(s) or device(s) that has not and cannot be easily removed . 3.2.16 Subjects who have implanted medical devices that pose high risks for colonization and cannot be easily removed (e.g., artificial heart valves, pacemakers, prosthetic joints, orthopedic screw(s), metal plate(s)) if infect ion occurs. Other common devices such as venous access devices (e.g., Port -a-Cath or Mediport) may be permitted as well as arterial and venous stents and dental and breast implants. 3.2.17 Evidence of clinical ascites. Trace or small amounts of radiograp hic ascites may be approved by the Protocol Chair. 3.2.18 Have clinically significant and/or malignant pleural effusion ( pleural effusions that are not clinically significant are allowed, defined as no more than 25% fluid level of the corresponding hemithorax and stable fluid level [non -progressive] over at least 6 weeks documented radiographically ). 3.2.19 Have had a new pulmonary emboli sm, extremity deep venous thromboembolism , or portal vein thrombosis within 2 months of study enrollment (any thrombosis within 2 months of study enrollment may be approved by the Protocol Chair) . 3.2.20 Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectori s, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements. 3.2.21 Subjects with active, known or suspected autoimmune disease. Subjects with Graves or Hashimoto’s disease, vitiligo, type I diabetes mellitus, psoriasis not requiring systemic treatment, or conditions not expected to recur in the absence of J1790 / Version 7.0/ December 10, 2020 15 an external trig ger are permitted to enroll. 3.2.22 Presence of any tissue or organ allograft, regardless of need for immunosuppression, including corneal allograft. Instances where loss of the graft is not a clinical concern (such as dental bone grafts or skin grafts p laced only to promote skin growth) can be approved by the Protocol Chair. Patients with a history of allogeneic hematopoietic stem cell transplant will be excluded. 3.2.23 All toxicities attributed to prior anti -cancer therapy other than alopecia and fati gue must have resolved to grade 1 ( National Cancer Institute Common Terminology Criteria for Adverse Events [ CTCAE ], version 4 .03) or baseline before administration of study drug. Subjects with toxicities attributed to prior anti -cancer therapy which are not expected to resolve and result in long-lasting sequelae, such as neuropathy after chemo therapy, are permitted to enroll. 3.2.24 Have received a diagnosis of human immunodeficiency virus (HIV), hepatitis B or hepatitis C (patients who are hepatitis C antibody positive may be enrolled if they are confirmed with negative viral load at screening) 3.2.25 Patient has a pulse oximetry of <92% on room air . 3.2.26 Patient is on supplemental home oxygen . 3.2.27 Patient has an unhealed surgical wound or ulcer, or a bone fracture considered non - healing . 3.2.28 Patient has clinically significant heart disease (such as uncontrolled angina, myocardial infarction within the last 3 months or congestive heart failure of New York Heart Association III or IV) . 3.2.29 Patient has valvular heart disease that requires antibiotic prophylaxis for prevention of endocarditis . 3.2.30 Have insufficient peripheral venous access to permit completion of the study dosing and compliance with study phlebotomy regimen 3.2.31 Patient is, at the time of signing informed consent, a regular user (including “recreational use”) of any illicit drugs or other substance abuse (including alcohol) that could potentially interfere with adherence to study procedures or requirements. 3.2.32 Patient is unwilling or unable to follow the study schedule for any reason . 3.2.33 Patient is pregnant or breastfeeding . 3.2.34 Have rapidly progressing disease, as judged by the investigator (e.g., rapid progression through prior treatment[s]) . J1790 / Version 7.0 / December 10, 2020 16 3.3 Inclusion of Women and Minorities Both men and women of all races and ethnic groups are eligible for this trial. 4. REGISTRA T ION, RANDOMIZATION , AND BLINDING 4.1 General Guidelines Eligible patients will be entered on study centrally at the Sidney Kimmel Comprehensive Cancer Center at the Johns Hopkins University by the Lead Study Coordinator. All sites should conta ct the Lead Study Coordinator to verify ongoing study enrollment. The Registration Form and Eligibility Checklist will be supplied to each participating site. If a patient does not receive protocol therapy following registration, the patient’s registratio n on the study may be canceled. The Study Coordinator should be notified of cancellations as soon as possible. 4.2 Registration Process To register a patient, the following de - identified documents should be completed and sent to the Lead Study Coordinat or at • Fax cover sheet • Registration Form • Signed patient consent form • Eligibility Checklist • Copy of required screening tests and scans The Research Nurse or Study Coordinator at the participating site will then e - mail the Protocol Chair to verify eligibility. To complete the registration process, the Lead Study Coordinator will: • Assign a patient study number • Register the patient on the study • Fax or e - mail the patient study number to the participating site • Call or e - mail the research nurse or data manager at the participating site and verbally confirm registration. 4.3 Randomization This study is an open - label study .