This is a phase 1, open-label, multicentric study evaluating the safety, feasibility and efficacy of ODI-2001, a personnalized therapeutic cancer vaccine composed of DNA neoantigen vaccine, Modified Vaccinia virus Ankara (MVA) viral adjuvant and anti-CTLA4 (ipilimumab), in patients with metastatic or locally advanced colorectal or pancreatic cancer. The study includes a dose-escalation phase to determine the maximum tolerated dose (MTD) followed by an expansion phase to evaluate efficacy in terms of progression-free survival