• Patient must be female ≥ 19 years of age

• Histologic confirmation of the original primary tumor is required. Patients with the following histologic types are eligible: Endometrioid adenocarcinoma, serous adenocarcinoma, undifferentiated carcinoma, clear cell adenocarcinoma, mixed epithelial carcinoma, carcinosarcoma, adenocarcinoma not otherwise specified (N.O.S.).

• Measurable stage III, measurable stage IVA, stage IVB (with or without measurable disease) or recurrent (with or without measurable disease) endometrial cancer.

• MMR proficient confirmed by institutional (local) MMR IHC testing.

• Patient must provide the institutional (local) P53 IHC result.

• Prior Therapy;

‣ Naïve to first line systemic anti-cancer treatment. For patients with recurrent disease only, prior systemic anti-cancer treatment is allowed only if provided adjuvant chemotherapy was completed ≥ 12 months prior to randomization.

‣ a. Note : For Part A(Safety lead in phase), patient who used Paclitaxel, Carboplatin and Pembrolizumab for first line systemic therapy can participate if they meet all of the following conditions. Patient must have had 6 cycles of chemotherapy; patient must have physician assessed stable disease (SD), partial response (PR), or complete response (CR) after 6 cycles of therapy and patient must be enrolled within 9 weeks of their last dose of chemotherapy (last dose is the day of the last infusion)

⁃ Patients may have received prior radiation therapy for treatment of endometrial cancer. Prior radiation therapy may have included pelvic radiation therapy, extended field pelvic/para-aortic radiation therapy, and/or intravaginal brachytherapy. All radiation therapy must be completed at least 4 weeks prior to randomization.

⁃ Patients may have received prior hormonal therapy for treatment of endometrial cancer. All hormonal therapy must be discontinued at least three weeks prior to randomization.

• Archival tumor tissue available or a fresh biopsy must be obtained prior to randomization.

• Eastern Cooperative Oncology Group (ECOG) performance status 0, 1 or 2

• Have adequate organ function. Specimens must be collected within 7days prior to the start of study intervention.

• \- Hematology Absolute neutrophil count (ANC) ≥1,500/μL without growth factor support within 2 weeks before screening test.

• Platelet ≥100,000/μL without transfusion within 2 weeks prior to screening test.

• Hemoglobin ≥10.0 g/dL without transfusion within 2 weeks prior to screening test.

⁃ Kidney function Creatinine or measured or calculated creatinine clearance (GFR may also be used in place of creatinine or CrCl a) ≤1.5 × ULN or ≥30 mL/min for subjects with creatinine levels \>1.5 × institutional ULN.

⁃ liver function Total bilirubin ≤1.5×ULN or direct bilirubin ≤ULN for subjects whose total bilirubin exceeds 1.5 times the normal value.

• AST (SGOT) and ALT (SGPT) ≤3 × ULN (≤5 × ULN in subjects with liver metastases)

⁃ Coagulation International normalized ratio (INR) or prothrombin time (PT) Activated partial thromboplastin time (aPTT) ≤1.5

⁃ Thyroid function Thyroid stimulating hormone (TSH) within normal limits (WNL); In euthyroid subjects receiving thyroid replacement therapy, TSH \< ULN; If an abnormal TSH result is shown, free T4 is normal, and glandular function (euthyroid) is clinically normal, registration is possible.

⁃ Patient has voluntarily agreed to participate by giving written informed consent/assent for the trial.

⁃ Women of childbearing potential (WOCBP) must agree to use adequate contraception (hormonal method or abstinence, contraceptive procedure (IUD, Mirena, etc.)) from up to 14 days prior to randomization (for oral contraceptives), during treatment, and for 6 months after the last dose of Paclitaxel + Carboplatin, for 4 months after the last dose of Pembrolizumab, for 3 months after the last dose of Nesuparib, whichever occurs last.

⁃ Should a woman become pregnant or suspect she is pregnant while she is participating in this study, she should inform her treating physician immediately. Patients will be considered of nonreproductive potential if they are either:

∙ Postmenopausal (defined as at least 12 months with no menses without an alternative medical cause; in women \<45 years of age, a high follicle stimulating hormone (FSH) level in the postmenopausal range may be used to confirm a postmenopausal state in women not using hormonal contraception or hormonal replacement therapy. In the absence of 12 months of amenorrhea, a single FSH measurement is insufficient); OR

‣ Have a hysterectomy and/or bilateral oophorectomy, bilateral salpingectomy or bilateral tubal ligation/occlusion, at least 6 weeks prior to randomization; OR Have a congenital or acquired condition that prevents childbearing.