6. DOSING DELAYS/DOSE MODIFICATIONS Dose delays and modifications will be made as indicated in the following sections. The descriptions and grading scales found in the revised NCI Common Terminology Criteria for Adverse Events (CTCAE) version 4.0 will be utilized for dose delays and dose modifications. A copy of the CTCAE version 4.0 can be downloaded from the DF/HCC Protocol #: 18-280 Protocol Version Date: 10.17.2020 20 CTEP website http://ctep.cancer.gov/protocolDevelopment/electronic_applications/ctc.htm . 6.1 Dose Delays To initiate cycle 1 of therapy with vaccine and nivolumab, participants must meet the eligibility criteria outlined in section 3.3. Patients experiencing any of the following toxicities judged to be possibly or definitely related to study treatment will not receive further therapy.  Grade 3 or higher non-hematologic toxicities that do not resolve within 14 days of onset; o Please note the following exceptions indicated in Appendix B that necessitate immediate discontinuation of therapy:  Grade 4 creatinine elevation  Grade 3 or higher pulmonary toxicity  ALT/AST or total bilirubin grade 3 or higher elevation  Grade 3 or higher adrenal insufficiency  Grade 3 or higher neurological adverse event  Grade 3 or higher myocarditis  Grade 4 or higher non-hematologic toxicities;  Grade 4 or higher hematologic toxicities that do not resolved within 7 days of onset; o Please note that this excludes lymphopenia, as mentioned in section 5.9.3;  Grade 4 or higher nivolumab infusion reactions.  Laboratory abnormalities that are not thought to be clinically significant (i.e. lymphopenia) will not be included in criteria for holding of therapy Patients experiencing grade 3 non-hematologic toxicity, grade 2 immune associated toxicity as outlined in Appendix B, and grade 4 hematologic toxicity will have therapy held. Patients not meeting these criteria may have therapy held for clinical reasons with the approval of the study PI or designee. Patients who experience grade 4 hematologic toxicity that resolves to grade 1 or baseline within 7 days OR grade 3 non-hematologic toxicity that resolves to grade 0-1 within 14 days OR grade 2 immune associated toxicity requiring hold of therapy as outlined in Appendix B that resolves to grade 0-1 within 14 days may have therapy restarted UNLESS otherwise specified in Appendix B. Therapy is restarted at the point of dose interruption so that all intended doses of vaccine and nivolumab are administered. Patients experiencing recurrence grade 3 non-hematologic toxicity, grade 2 immune associated toxicity as outlined in Appendix B, and grade 4 hematologic toxicity will have therapy discontinued UNLESS otherwise specified in Appendix B. To initiate cycles 2-6 of therapy, subjects must not have any evidence of TLT as outlined above or in section 7. In the event that the toxicity is clearly related to nivolumab alone (such as infusion reactions) and meets criteria for discontinuation, patients may continue to receive vaccine alone per protocol. Patients experiencing immune-related adverse events may be treated with corticosteroids (up to prednisone of 1 mg/kg or equivalent). Patients who improve to grade 1 or less in this context as outlined above AND who can be tapered to prednisone of 10 mg or equivalent or less may continue on therapy. There will be no dose modifications.