A Study of Adjuvant Pembrolizumab/Vibostolimab (MK-7684A) Versus Pembrolizumab for Resected High-Risk Melanoma in Participants With High-Risk Stage II-IV Melanoma (MK-7684A-010/KEYVIBE-010)

Inclusion Criteria:

• Has surgically resected and histologically or pathologically confirmed diagnosis ofStage IIB and IIC (pathological or clinical), III, or IV cutaneous melanoma per theAmerican Joint Committee on Cancer (AJCC) eighth edition guidelines

• Has not received any prior systemic therapy for melanoma beyond surgical resection

• Has had no more than 12 weeks between final surgical resection and randomization

• Human immunodeficiency virus (HIV)-infected participants must have well controlledHIV on anti-retroviral therapy (ART)

• Participants who are hepatitis B surface antigen (HBsAg) positive are eligible ifthey have received hepatitis B virus (HBV) antiviral therapy for at least 4 weeksand have undetectable HBV viral load before randomization

• Participants with history of hepatitis C virus (HCV) infection are eligible if HCVviral load is undetectable at screening

Exclusion Criteria:

• Has ocular, mucosal, or conjunctival melanoma

• 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 ofimmunosuppressive therapy within 7 days prior the first dose of study medication

• Has not adequately recovered from major surgical procedure or has ongoing surgicalcomplications

• Has received prior radiotherapy within 2 weeks of start of study intervention or hashad a history of radiation pneumonitis

• Received a live or live attenuated vaccine within 30 days before the first dose ofstudy intervention. Administration of killed vaccines is allowed

• Has received an investigational agent or has used an investigational device within 4weeks before study intervention administration

• Has a history of (noninfectious) pneumonitis/interstitial lung disease that requiredsteroids or has current pneumonitis/interstitial lung disease

• Has a known additional malignancy that is progressing or has required activetreatment within the past 3 years

• Has known active central nervous system (CNS) metastases and/or carcinomatousmeningitis

• Has an active autoimmune disease that has required systemic treatment in past 2years

• Has an active infection requiring systemic therapy

• Has had an allogenic tissue/solid organ transplant