Abstract: Biliary tract cancers (BTCs), encompassing gallbladder cancer and intra- and extra-hepatic cholangiocarcinoma, primarily manifest as highly invasive adenocarcinomas with a notably poor prognosis. BTCs typically initiate insidiously, and even surgically resectable patients confront a heightened risk of recurrence, with postoperative adjuvant chemotherapy offering limited survival benefits. For unresectable or metastatic BTCs, systemic antitumor drug therapy remains the primary treatment. Recently, significant progress has been made in the treatment of advanced BTCs with the emergence of immune checkpoint inhibitors (ICIs) and molecularly targeted drugs alongside traditional chemotherapy. This progress has substantially broadened clinical treatment options and improved patient prognoses. Combining first-line chemotherapy with immunotherapy has emerged as a favorable treatment strategy over conventional chemotherapy. Additionally, the combination of chemotherapy with immunotherapy, anti-angiogenic targeted therapy, dual immunotherapy, or dual immunotherapy has exhibited promising outcomes. Explorations into second-line immunotherapy have also been actively explored. This article provides an overview of the current status and recent advances in immunotherapy for advanced BTCs.