Abstract: Biliary tract cancer (BTC) is one of the most aggressive malignancies with only 10% earlystage diagnosis rate. For advanced BTC, regimen of gemcitabine and cisplatin has been regarded as the first line standard combination, but the curative effect is still unsatisfied. Infiltration of immune cells and immunerelated microenvironment can inhibit various types of cancers. In BTC, higher frequencies of tumorinfiltrating CD8+ cytotoxic T cells and CD4+  T cells are closely associated with favorable prognosis. These findings have provided the rationale for further development of immunotherapies as a novel treatment modality against BTC.

Key words: Biliary tract neoplasms, Immunotherapy