A Study of Nivolumab Alone or Nivolumab Combination Therapy in Colon Cancer That Has Come Back or Has Spread

Inclusion Criteria:

Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1
Histologically confirmed recurrent or metastatic colorectal cancer
Measurable disease per RECIST v1.1
Microsatellite instability expression detected by an accredited laboratory
Participants enrolled into the C3 Cohort must have not had treatment for their metastatic disease

Exclusion Criteria:

Active brain metastases or leptomeningeal metastases are not allowed
Prior treatment with an anti-Programmed Death Receptor (PD)-1, anti-PD-L1, anti-PD-L2, anti-Cytotoxic T-Cell Lymphoma-4 Antigen (CTLA-4) antibody, or any other antibody or drug specifically targeting T-cell co-stimulation or immune checkpoint pathways
Prior malignancy active within the previous 3 years except for locally curable cancers
Participants with active, known or suspected autoimmune disease
Participants with a condition requiring systemic treatment with either corticosteroids or other immunosuppressive medications within 14 days of study drug administration

Other protocol-defined inclusion/exclusion criteria apply