A Prospective, Randomized Controlled Study of Cyclophosphamide, Bevacizumab With or Without Envafolimab in Recurrent Epithelial Ovarian Cancer (EOC), Fallopian Tube Cancer, and Primary Peritoneal Cancer

Inclusion Criteria: * Age 18-70 years Histologically or pathologically confirmed epithelial ovarian cancer (EOC), fallopian tube cancer, primary peritoneal cancer Patients with recurrent ovarian, fallopian tube, and primary peritoneal cancer following platinum-based chemotherapy measurable lesions (according to RECIST 1.1 criteria, non-lymph node lesions CT scan long diameter ≥ 10 mm, lymph node lesions CT scan short diameter ≥ 15 mm) ECOG PS score: 0 - 1; Exclusion Criteria: * Subject has prior or concurrent other malignancy Prior treatment with other PD-L1/PD-L1 inhibitors cannot be enrolled; Subject has known previous hypersensitivity to macromolecular protein preparations or applied drug components