Inclusion Criteria:  ECOG Performance status of 0 or 1. Pathologically (histologically) confirmed diagnosis of potentially resectable Stage II or Stage III CRC with MSI-H confirmed by sponsor designated central laboratory. Participants should be eligible for an R0 resection with curative intent. Evaluable or measurable disease as assessed by the investigator per RECIST v1.1. Adequate hematologic and organ function, defined by protocol-specified laboratory test results, obtained within 14 days before first dose.  Exclusion Criteria:  Any prior therapy for current CRC, including chemotherapy or radiotherapy or immunotherapy. Any condition requiring systemic treatment with either corticosteroids (> 10 mg daily prednisone or equivalent) or other immunosuppressive medications within 14 days before first dose. Active autoimmune diseases or history of autoimmune diseases that may relapse.  Note: Other protocol defined Inclusion/Exclusion criteria may apply.