Pembrolizumab is a programmed cell death protein (PD-1) inhibitor, humanized antibody widely used in cancer immunotherapy. Choriocarcinoma is an aggressive type of gestational trophoblastic neoplasia. Its treatment is based on surgical removal of the tumorous tissue and systemic chemotherapy; however, in some chemoresistant cases, immunotherapy can also be a valid option. Here, we report the first successful programmed death inhibitor-based treatment of a patient diagnosed with stage IV, ultra-high-risk choriocarcinoma in Hungary.