RecruitingPhase 2Drug trialStudy of Induction PD-1 Blockade (Nivolumab) in Patients With Surgically Complete Resectable Mismatch Repair Deficient Endometrial Cancer (NIVEC)phase 2 clinical trial to confirm the pathological complete response rate of PD-1 blocker use in patients with Mismatch Repair Deficiency(MMRd) endometrial cancer that can be completely resected surgically.