Pembrolizumab With Chemotherapy and MK-4830 for Treating Participants With Ovarian Cancer (MK-4830-002)

Has a non-HGSOC histology.Has a history of (noninfectious) pneumonitis/interstitial lung disease that required steroids or has current pneumonitis/interstitial lung disease. Has a known additional malignancy that is progressing or has required active treatment within the past 3 years. Has received prior treatment for any stage of OC, including radiation or systemic anticancer therapy. Planned or has been administered intraperitoneal chemotherapy as first-line therapy. Has received prior therapy with an anti-programmed cell death 1 protein (PD-1), anti-programmed cell death 1 ligand 1 (PD-L1), anti-programmed cell death 1 ligand 2 (PD-L2), anti-immunoglobulin-like transcript 4 (ILT4), or anti-human leukocyte antigen (HLA)-G agent or with an agent directed to another stimulatory or coinhibitory T-cell receptor. Has received a live or live-attenuated vaccine within 30 days before the first dose of study intervention. Is 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. 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 prior the first dose of study medication. Has known active Central Nervous System (CNS) metastases and/or carcinomatous meningitis. Has severe hypersensitivity to pembrolizumab, carboplatin, paclitaxel (or docetaxel, if applicable), Avastin or biosimilar (if using) and/or any of their excipients. Has an active autoimmune disease that has required systemic treatment in past 2 years. Has an active infection requiring systemic therapy. Has a known history of human immunodeficiency virus (HIV) infection. Has a known history of hepatitis B or known active hepatitis C virus infection. Has received colony-stimulating factors within 4 weeks prior to receiving study intervention on Day 1 of Cycle 1. Has had surgery <6 months prior to Screening to treat borderline ovarian tumors, early-stage OC, or early-stage fallopian tube cancer. Has a known psychiatric or substance abuse disorder that would interfere with the participant's ability to cooperate with the requirements of the study. Has current, clinically relevant bowel obstruction. Has a history of hemorrhage, hemoptysis, or active gastrointestinal (GI) bleeding within 6 months prior to randomization. Has uncontrolled hypertension. Has had an allogenic tissue/solid organ transplant. .Has either had major surgery within 3 weeks of randomization or has not recovered from any effects of any major surgery.