[Whole view of the immune microenvironment of biliary tract cancer].

Biliary tract cancer is a group of malignancies which originate from biliary epithelium, and adenocarcinoma is the main pathological type. Although surgical resection is the only radical treatment strategy, most biliary tract cancer patients are diagnosed at locally advanced stage or with distant metastasis. Biliary tract cancer is highly resistant to the conventional chemoradiotherapy and the emerging immunotherapy including immune checkpoint inhibitors, owing to the suppressive immune microenvironment. In a whole view, this paper discussed the anti-tumor and tumor-promoting immune responses of the various immune cells and stromal cells in the immune microenvironment of biliary tract cancer, as well as their correlation with prognosis. The understanding of the whole view of immune microenvironment in biliary tract cancer patients could further inform the design of clinical trials of immunotherapy or combination therapy.