RecruitingPhase 2Drug trialPhase II Investigation of Pembrolizumab in Combination With Bevacizumab and Oral Cyclophosphamide in Patients With High Grade Ovarian Cancer and Surgically Documented Minimal Residual Disease After Frontline TherapyTo find out if combining pembrolizumab, bevacizumab (or an equivalent biosimilar drug), and low-dose cyclophosphamide can help control high-grade ovarian cancer that has MRD after treatment. The safety of this treatment combination will also be studied.