A Study to Evaluate the Safety and Efficacy of Two Dose Levels of ONO-4578 With Opdivo®, in Combination With mFOLFOX6 and Bevacizumab Versus Standard of Care in Participants With Non-MSI-H/dMMR, PD-L1 Positive Advanced Colorectal Cancer

Inclusion Criteria: * Histologically confirmed advanced (locally advanced or metastatic) colorectal cancer not amenable to curative resection * ECOG Performance Status of 0-1 * No prior systemic treatment for advanced local or mCRC * Participants whose tumor is positive for PD-L1 expression as determined at a central laboratory Exclusion Criteria: * Participants with high microsatellite instability (MSI-High), or mismatch repair deficient (dMMR) tumor * Participants with BRAF V600E mutation * Unable to swallow tablets. * Participants with complication or history of interstitial lung disease, pneumonitis or pulmonary fibrosis * Participants with an active, known or suspected autoimmune disease. * Prior treatment with an anti-PD-1, anti-PD-L1, anti-PD-L2, or anti-CTLA-4 antibody, or any other antibody or drug specifically targeting T-cell co-stimulation or immune checkpoint pathways. Other protocol-defined inclusion/exclusion criteria apply