- Active or untreated central nervous system metastases - Malignancies other than NSCLC within 5 years prior to randomization, with the exception of those with a negligible risk of metastasis or death treated with the expected curative outcome - Pregnant or lactating women - History of autoimmune disease - History of idiopathic pulmonary fibrosis, organizing pneumonia, drug-induced pneumonitis, idiopathic pneumonitis, or evidence of active pneumonitis on screening chest computed tomography scan. History of radiation pneumonitis in the radiation field (fibrosis) is permitted. - Positive test for human immunodeficiency virus - Active hepatitis B or hepatitis C - Severe infection within 4 weeks prior to randomization - Significant cardiovascular disease - Illness or condition that interferes with the participant's capacity to understand, follow and/or comply with study procedures - Prior treatment with a cluster of differentiation 137 agonists or immune checkpoint blockade therapies, anti-programmed death-1, and anti-PD-L1 therapeutic antibodies.