• Participants must have histologically or cytologically confirmed recurrent or persistent clear cell carcinoma of the ovary (CCOC) or clear cell carcinoma of other gynecologic origin (e.g., endometrial, cervical, vaginal, vulvar, endometriosis-related). If mixed histology, then ≥50% clear cell component.

• Participants must have measurable disease, defined as at least one lesion that can be accurately measured per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 criteria. Lesions situated in a previously irradiated area are considered measurable if progression has been demonstrated in such lesions.

• Participants must have received at least one prior platinum-based chemotherapeutic regimen for primary management of disease.

• Prior bevacizumab is allowed.

• Prior use of immunotherapy is allowed.

• Unlimited prior lines for the treatment of recurrent or persistent disease are allowed.

• Age ≥18 years. Because no dosing or adverse event data are currently available on the use of Belzutifan in participants \<18 years of age, children are excluded from this study.

• ECOG (Eastern Cooperative Oncology Group) performance status of 0 or 1 (Karnofsky performance scale ≥70%, see Appendix A).

• Participants must meet the following organ and marrow function as defined below:

‣ Absolute neutrophil count ≥ 1,500/mcL

⁃ Hemoglobin ≥ 10.0 g/dL (without use of erythropoietin; without packed red blood cell (RBC) transfusion within preceding 2 weeks)

⁃ Platelets ≥ 100,000/mcL

⁃ Total bilirubin ≤ 1.5 x institutional upper limit of normal (ULN) OR direct bilirubin ≤ ULN for participants with total bilirubin levels \> 1.5 ULN

⁃ AST(SGOT)/ALT(SGPT) ≤ 2.5 × institutional upper limit of normal (ULN) (in the absence of liver metastases) or ≤ 5 x institutional ULN (in the presence of liver metastases)

⁃ Creatinine ≤ 1.5 x institutional upper limit of normal (ULN) OR estimated creatinine clearance (CrCl) by the Cockcroft-Gault formula

‣ ≥51mL/min if creatinine \> 1.5 x institutional ULN or institutional standard method

⁃ INR OR PT and PTT ≤1.5 × institutional ULN unless participant is receiving anticoagulant therapy and PT/INR or PTT are within therapeutic range of that anticoagulation

• Participants with known brain metastases are eligible if they have completed primary CNS-directed therapy (such as surgical resection or radiotherapy) and if they have remained clinically stable, asymptomatic, radiologically stable without evidence of progression for at least 4 weeks by repeat imaging and have been off of steroids for at least 4 weeks prior to starting study treatment.

• Participants with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the Belzutifan, as determined after discussion with the Sponsor-Investigator, are eligible for this trial.

• Archival tumor tissue must be available as 17 (15 unstained + 2 H\&E) freshly serially cut slides from formalin-fixed, paraffin-embedded (FFPE) tissue blocks. The most recent available tissue is preferred to archived tissue. If fewer than 17 slides are available, the participant may still be eligible pending discussion with the Sponsor-Investigator.

• The effects of Belzutifan on the developing human fetus are unknown. For this reason, women of child-bearing potential\* must have a negative serum or urine pregnancy test at the Screening and Cycle 1 Day 1 visits. A negative serum or urine pregnancy test must be obtained within 24 hours before the first dose of study intervention in order to start receiving the study drug. Women of child-bearing potential and men must agree to use adequate contraception (see Appendix D) prior to study entry, for the duration of study participation, and for at least 30 days after last receipt of study therapy. Additionally, should a woman become pregnant or suspect she is pregnant while she is participating in this study, she should inform her treating physician immediately.

⁃ -Female participants who do not meet the definition of women of child-bearing potential must meet either criteria:

⁃ Post-menopausal, defined as amenorrheic for at least 12 consecutive months within the appropriate age group and without an alternative medical cause OR

⁃ Surgically sterilized (i.e. bilateral oophorectomy, bilateral tubal ligation or salpingectomy, or total hysterectomy)

• Ability to swallow orally administered medications.

• Ability to understand and the willingness to sign a written informed consent document.