Exclusion criteria for the vaccine production stage. Patients meeting any of the following criteria are not eligible for enrollment in the vaccine production stage: 1. Tumors with genetic characteristics as follows: a. For NSCLC, patients with a known genetic driver alteration in EGFR, ALK, ROS1, RET or TRK b. For CRC and GEA, patients with known microsatellite instability-high disease based on institutional standard c. For CRC, patients with a known BRAF V600E mutation or patients with peritoneal carcinomatosis, and for GEA, patients with peritoneal carcinomatosis as their only evidence of disease 2. Patient has a known tumor mutation burden more than one nonsynonymous mutations/megabase. 3. Known exposure to ChAd or any history of anaphylaxis in reaction to a vaccination or allergy or hypersensitivity to study drug components. 4. Bleeding disorder (e.g., factor deficiency or coagulopathy) or history of substantial bruising or bleeding following i.m. injections or blood draws.