Advanced endometrial clear cell carcinoma (CCC) tends to have poor prognosis owing to aggressive clinical behavior and poor response to conventional chemotherapy. Herein, we report a case of platinum-refractory recurrent ECCC successfully treated with the combination of pembrolizumab, localized radiotherapy and a few cycles of chemotherapy with an extremely durable response even after cessation of immunotherapy for 3 years at the time of publication.