Immune checkpoint inhibitors and combinations with other agents in cholangiocarcinoma

Cholangiocarcinoma consists of a heterogeneous group of malignancies with generally poor prognoses. Immunotherapy has emerged in the treatment landscape of many tumors, offering survival benefits, but data regarding the use of immunotherapy for cholangiocarcinoma remain vague. In this review, the authors analyze differences in the tumor microenvironment and various immune escape mechanisms and discuss available immunotherapy combinations with other agents among completed and ongoing clinical trials, such as chemotherapy, targeted agents, antiangiogenic drugs, local ablative therapies, cancer vaccines, adoptive cell therapy and PARP and TGF-β inhibitors. Ongoing research to identify appropriate biomarkers is warranted.