For more information regarding Bristol Myers Squibb Clinical Trial participation, please visit www.BMSStudyConnect.com Inclusion Criteria prior to Surgery: - Suspected or histologically confirmed Stage IIA to IIIB NSCLC with disease that is considered resectable - Must be deemed eligible for complete resection and must agree to undergo standard of care surgery for complete resection of NSCLC - Treatment naive (no previous systemic treatment) Inclusion Criteria prior to Treatment Randomization: - Must have undergone complete surgical resection of their Stage IIA to IIIB NSCLC - Must have adequately recovered from surgery at the time of randomization - Minimal residual disease (MRD) positive results as detected by ctDNA Exclusion Criteria prior to Surgery: - Participants with known EGFR mutations which are sensitive to available targeted inhibitor therapy (Prior to treatment randomization in select sites) - Active, known or suspected autoimmune disease - Participants with a condition requiring systemic treatment with either corticosteroids (> 10 mg daily prednisone equivalent) or other immunosuppressive medications within 14 days of randomization Exclusion Criteria prior to Treatment Randomization: - Must continue to meet Exclusion Criteria prior to Surgery - Must have no evidence of metastatic disease after surgery - Received a live/attenuated vaccine within 30 days of first treatment Other protocol defined inclusion/exclusion criteria could apply