Study of Pembrolizumab/Vibostolimab Coformulation (MK-7684A) in Combination With Chemotherapy Versus Pembrolizumab Plus Chemotherapy in Participants With Metastatic Non-Small Cell Lung Cancer (MK-7684A-007/KEYVIBE-007)

Inclusion Criteria

The main inclusion and exclusion criteria include but are not limited to the following: - A histologically or cytologically confirmed diagnosis of Stage IV squamous or non-squamous NSCLC. - Has not received prior systemic treatment for metastatic NSCLC. - Has measurable disease based on RECIST 1.1, as determined by the local site assessment. - Has a life expectancy of at least 3 months. - Males: Use contraception unless confirmed to be azoospermic; Females: Women of childbearing potential use highly effective contraceptive method.

Exclusion Criteria

- Known additional malignancy that is progressing or has required active treatment within the past 3 years. - Known active central nervous system (CNS) metastases and/or carcinomatous meningitis. - Severe hypersensitivity to vibostolimab, pembrolizumab, chemotherapy components, and/or any of its excipients. - 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 medication. - Active autoimmune disease that has required systemic treatment in past 2 years (ie, with use of disease modifying agents, corticosteroids, or immunosuppressive drugs). Replacement therapy (eg, thyroxine, insulin, or physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency) is not considered a form of systemic treatment and is allowed. - History of (noninfectious) pneumonitis/interstitial lung disease that required steroids or has current pneumonitis/interstitial lung disease. - Has an active infection requiring systemic therapy. - Has a known history of human immunodeficiency virus (HIV), Hepatitis B or/and Hepatitis C virus. - Received prior systemic anticancer therapy for metastatic disease. - Received a live or live attenuated vaccine within 30 days before the first dose of study intervention. Administration of killed vaccines are allowed. - History of allogenic tissue/solid organ transplant. - Is unable to interrupt aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs), other than an aspirin dose ≤1.3 g/day, for a 5-day period (8-day period for long-acting agents, such as piroxicam). - Is unable or unwilling to take folic acid or vitamin B12 supplementation. - Currently participating in or has participated in a study of an investigational agent or has used an investigational device within 4 weeks before the first dose of study intervention.