Condition: Metastatic Non-Small Cell Lung Cancer

This study is to assess the pharmacokinetics (PK) and safety of SC MK-3475A vs intravenous (IV) pembrolizumab, administered with chemotherapy in first line treatment of adult participants with metastatic non-small cell lung cancer. The primary hypotheses of this study are MK-3475A subcutaneous (SC) is noninferior to pembrolizumab IV with respect to PK parameters.