M7824 Versus Pembrolizumab as a First-line (1L) Treatment in Participants With Programmed Death-ligand 1 (PD-L1) Expressing Advanced Non-small Cell Lung Cancer (NSCLC)

Inclusion Criteria: * Histologically confirmed diagnosis of advanced NSCLC * Have not received prior systemic therapy treatment for their advanced/Stage four NSCLC. Completion of treatment with cytotoxic chemotherapy, biological therapy, and/or radiation as part of neoadjuvant/adjuvant therapy is allowed as long as therapy was completed at least 6 months prior to the diagnosis of metastatic disease. Confirmation of resolution of toxic effects of previous neoadjuvant/adjuvant chemotherapy therapy to Grade less than or equal to 1. For radiation toxicity or prior major surgeries, participants should have recovered from side effects and/or complications * Have measurable disease based on RECIST 1.1 * Have a life expectancy of at least 3 months * Availability of tumor tissue (less than 6 months old) before the first dose is mandatory to determine PD-L1 expression level prior to enrollment * PD-L1 high status as determined by central testing * Other protocol defined inclusion criteria could apply Exclusion Criteria: * Participants with nonsquamous NSCLC histologies whose tumor harbors any of the following molecular alterations and targeted therapy is locally approved: epidermal growth factor receptor (EGFR) sensitizing (activating) mutation, anaplastic lymphoma kinase (ALK) translocation, ROS1 rearrangement, or BRAF V600E mutation * Has received major surgery within 4 weeks prior to the first dose of study intervention; received thoracic radiation therapy of greater than 30 units of gray (Gy) within 6 months prior to the first dose of study * Known severe hypersensitivity to investigational products (M7824 or pembrolizumab), or any components in their formulations * Previous malignant disease (other than the target malignancy to be investigated in this study) within the last 3 years * Other protocol defined exclusion criteria could apply