Review of existing MRI, x-ray, or CT images. Review of existing photographs or videos. Review of existing pathology specimens/reports from a specimen obtained for diagnostic purposes. 2.2.2 Screening activities performed after a consent for screening has been signed The following activities will be performed only after the subject has signed the study consent or the consent for study # 01C0129 (provided the procedures are permitted on that study) on which screening activities will be performed within 28 days prior to enrollment unless otherwise indicated. Assessments performed at outside facilities or on another NIH protocol within the timeframes below may also be used to determine eligibility once a participant has signed the consent. Complete medical history and physical examination (including height, weight, vital signs, and ECOG performance status). Imaging for Phase I: CT of chest, abdomen and pelvis or MRI, if clinically indicated. A brain CT scan in participants with known CNS disease as described in Section 2.1.2.3/ MRI scan if clinically indicated. Imaging for Phase II: CT of the neck and chest+, or MRI, if clinically indicated, for participants with oropharyngeal cancer. CT of skull, neck and chest+, or MRI, if clinically indicated, for participants with sinonasal SCC. +Imaging of chest and neck ± skull is preferred but not required if a PET/CT is available from within the screening timeframe. For skin lesions, documentation by color photography, including a ruler to estimate the size of the lesion. EKG Clinical laboratory tests (within 16 days prior to enrollment): oAcute care panel (Na+, K+, Cl-, total CO2, creatinine, glucose, blood urea nitrogen). oHepatic panel (AST/GOT, ALT/GPT, total bilirubin, direct bilirubin). 24 Abbreviated Title: Combo Immunotx in HPV OPSCC Version Date: 04.25.2023 oMineral panel (albumin, calcium total, magnesium total, phosphorus). oUrine or serum pregnancy test (β-HCG) for females of childbearing-potential and women < 12 months since the onset of menopause (within 5 days prior to enrollment). oHematology: complete blood count (CBC) with differential. oUrinalysis. HBV, HCV, HIV testing including viral load for HCV, HBV and HIV if clinically indicated (within 3 months prior to enrollment). CD4 testing may also be required for HIV+ participants. Participants with a history of ≥ grade 3 hypersensitivity reaction to monoclonal antibodies or M7824 will be evaluated by immunologist prior to enrollment. 2.3 PARTICIPANT REGISTRATION AND STATUS UPDATE PROCEDURES Registration and status updates (e.g., when a participant is taken off protocol therapy and when a participant is taken off-study) will take place per CCR SOP ADCR-2, CCR Participant Registration & Status Updates found at: https://ccrod.cancer.gov/confluence/pages/viewpage.action?pageId=73203825. 2.3.1 Screen Failure Screen failures are defined as participants who consent to participate in the clinical trial but are not subsequently assigned to the study intervention or entered in the study. A minimal set of screen failure information is required to ensure transparent reporting of screen failure participants, to meet the Consolidated Standards of Reporting Trials (CONSORT) publishing requirements and to respond to queries from regulatory authorities. Minimal information includes demography, screen failure details, eligibility criteria, and any serious adverse event (SAE).