KEYMAKER-U01 Substudy 01A: Efficacy and Safety Study of Pembrolizumab (MK-3475) With or Without Chemotherapy When Used With Investigational Agents in Treatment-naïve Participants With Stage IV Non-small Cell Lung Cancer (NSCLC) (MK-3475-01A/KEYMAKER-U01A)

The purpose of this study is to assess the efficacy and safety of pembrolizumab (MK-3475) with or without chemotherapy in combination with vibostolimab (MK-7684), boserolimab (MK-5890), MK-4830, MK-0482, I-DXd, or HER3-DXd in treatment-naïve participants with advanced squamous or non-squamous NSCLC. This study is one of the pembrolizumab substudies being conducted under one pembrolizumab umbrella master protocol (MK-3475-U01/KEYMAKER-U01).

Inclusion Criteria: The main inclusion criteria include but are not limited to the following: * Has histologically- or cytologically-confirmed diagnosis of Stage IV squamous or nonsquamous NSCLC * Participants with nonsquamous NSCLC who are not eligible for an approved targeted therapy * Is able to provide archival tumor tissue sample collected either within 5 years or within the interval from completion of last treatment but before entering the screening period or newly obtained core or excisional biopsy of a tumor lesion not previously irradiated obtained within 90 days of treatment initiation * Has not received prior systemic treatment for their metastatic NSCLC * Is able to complete all screening procedures within the 35-day screening window for Part A and 28-day screening window for Part B Exclusion Criteria: The main exclusion criteria include but are not limited to the following: * Has a diagnosis of small cell lung cancer * Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy (in dosing exceeding 10 mg daily of prednisone equivalent) or any other form of immunosuppressive therapy within 7 days before the first dose of study treatment * Has a known additional malignancy that is progressing or has required active treatment within the past 2 years * Has known active central nervous system (CNS) metastases and/or carcinomatous meningitis * Has an active autoimmune disease that has required systemic treatment in the past 2 years * Has a history of (noninfectious) pneumonitis that required steroids or has current pneumonitis * Has an active infection requiring systemic therapy * Has clinically significant cardiac disease, including unstable angina, acute myocardial infarction within 6 months from Day 1 of study treatment administration, or New York Heart Association Class III or IV congestive heart failure * Has a known history of human immunodeficiency virus (HIV) infection. Well-controlled HIV with anti-retroviral therapy (ART) is not excluded * Has a known history of Hepatitis B (HPV) or known active Hepatitis C virus infection. Hepatitis B surface antigen (HBsAg) positive is eligible if on HBV antiviral therapy for at least 4 weeks and HBV viral load is undetectable prior to randomization * Has had major surgery \