A Study to Evaluate the Efficacy of Pumitamig Versus Pembrolizumab in Participants With Previously Untreated Advanced Non-Small Cell Lung Cancer and PD-L1 ≥ 50%. (ROSETTA Lung-202)

The purpose of this study is to evaluate the efficacy of Pumitamig versus Pembrolizumab in participants with previously untreated advanced Non-Small Cell Lung Cancer and PD-L1 ≥ 50%.

Inclusion Criteria * Participants must have a histologically or cytologically confirmed diagnosis of Non-Small Cell Lung Cancer (NSCLC) (squamous and nonsquamous) with Stage IIIB/IIIC or Stage IV disease. * Participants must have a programmed death ligand-1 (PD-L1) expression ≥ 50%. * Participants must have measurable disease as defined by Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. * Participants must have no prior systemic anti-tumor therapy for locally advanced or metastatic NSCLC. * Participants must have an Eastern Cooperative Oncology Group (ECOG) Performance Status 0-1. Exclusion Criteria * Participants must not have any documented actionable genomic alteration (AGA) for which first-line (1L) approved therapies are indicated. * Participants must not have any symptomatic untreated central nervous system (CNS) metastases, leptomeningeal metastases (carcinomatous meningitis) or spinal cord compression. * Participants must not have any significant cardiovascular impairment as evidenced by uncontrolled hypertension (despite optimal medical treatment), congestive heart failure, active coronary disease (within 6 months prior to randomization), ventricular arrhythmias, or major thrombotic or embolic events or major hemorrhagic events (within 6 months prior to randomization), or significant risk of pulmonary hemorrhage. * Participants must not an active autoimmune disease. * Other protocol-defined Inclusion/Exclusion criteria apply.