Moreover, a recent study by Zhou et al. [144] proved that inhibition of PD-1 or CTLA-4 as well as induction of tumor necrosis factor receptor superfamily member 18 (GITR) increases the ex vivo effector functions of tumor-infiltrating T cells from patients with CCA, indicating that these may be promising targets for immunotherapy. Here, TNFRSF18 is linked to cholangiocarcinoma.