A Study of Novel Study Interventions and Combinations in Participants With Colorectal Cancer

Overall Inclusion Criteria: * Histopathologically confirmed colorectal adenocarcinoma. * Provision of FFPE tumor sample collected as per SoC. * Presence of measurable disease by RECIST 1.1 criteria. * ECOG performance status of 0 or 1. * Life expectancy ≥ 12 weeks at the time of screening. Substudy Inclusion Criteria: * No radiological evidence of liver metastasis. * No prior systemic therapy for mCRC, prior neoadjuvant/adjuvant chemotherapy is permitted only when given for resected (M0) disease and only after at least 6 months have elapsed since completion of that therapy and diagnosis of recurrent or metastatic disease. * Known pMMR/MSS status (only pMMR/MSS mCRC allowed). * Adequate organ and bone marrow function * Body weight \> 35 kg at screening and at randomization. * Contraceptive use by participants should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies. Overall Exclusion Criteria: * Central nervous system metastases or spinal cord compression * Known history of severe allergy to any monoclonal antibody or study intervention. * Any unresolved toxicity CTCAE Grade ≥ 2 from a previous anticancer therapy. * History of another primary malignancy. Substudy Exclusion Criteria: * Potentially resectable disease with multidisciplinary plan for radical surgery. * Active or prior documented autoimmune or inflammatory disorders or cardiac conditions. * Participants with a prior history of hypertensive crisis or hypertensive encephalopathy or bleeding risks. * Deep venous thrombosis, pulmonary embolism, arterial thrombosis, transient ischemic attack or cerebrovascular accident. * History of abdominal or tracheoesophageal fistula, GI perforation and/or fistulae, or intraabdominal abscess within 6 months prior to randomization. * Prior exposure to immune mediated therapy. * History of active primary immunodeficiency.