Pooled Mutant KRAS-Targeted Long Peptide Vaccine Combined With Nivolumab and Ipilimumab for Patients With Resected Mismatch Repair Protein (MMR-p) Colorectal and Pancreatic Cancer

Inclusion Criteria: PDAC or metastatic MSS CRC Cohort: * Have histologically or cytologically - proven cancer of the pancreas (PDA) or MSS colorectal (CRC) in one of the following categories: * PDAC must have no evidence of disease and last dose of neoadjuvant and/or adjuvant chemotherapy/radiation therapy/or surgery must be \< 6 months from study entry. * Metastatic MSS CRC after exposure to 2 more lines of chemotherapy in the metastatic setting including 5-flurouracil, irinotecan, and oxaliplatin exposure. Patients treated with FOLFOXIRI may enroll after progression or intolerance to that regimen. * For metastatic MSS CRC cohort, must have tumor lesions amenable to repeated biopsy, and patient's acceptance to have a tumor biopsy of an accessible lesion at baseline and on treatment if the lesion can be biopsied with acceptable clinical risk (as judged by the Principal Investigator). * For metastatic MSS CRC patients, must have measurable disease per RECIST 1.1. Reinduction Treatment Cohort: * Have a single site of locoregional recurrence or distant metastasis noted on imaging \> 12 months after the first dose of the mutant KRAS peptide vaccine with poly-ICLC adjuvant. * Have completed definitive treatment for solitary recurrence per standard-of-care (e.g. surgical resection, radiation, and/or chemotherapy) \<6 months prior to screening for reinduction treatment. Both Cohorts: \*Age ≥18 years. * Have sufficient archival tumor tissue for next-generation sequencing …