Following MTD/ RP2D declaration, patients will be enrolled in three phase II arms to assess efficacy of the combination as well as to better understand the safety, tolerability, PK, antibody concentrations and PD of the combination at MTD/RP2D. Phase II arm 1 will consist of approximately 25 patients with KRAS-mutant colorectal adenocarcinoma. Phase II arm 2 will consist of approximately 20 patients with metastatic pancreatic adenocarcinoma. Phase II arm 3 will consist of approximately 28 patients with mutant BRAFV600 melanoma.