IDO1 and cholangiocarcinoma: These included both immune-stimulatory and inhibitory genes, namely: FASLG, Galectin-9 (LGALS9), LAG-3, TIM-3 (HAVCR2), VSIR, VTCN1 (B7-H4), IDO-1, TNFRSF9 (CD137), TNFRSF14 (HVEM), TIGIT, CD276 (B7-H3), CD27, PD-L1 (CD274), PD-L2 (PDCD1LG2), NT5E (CD73), CD80, TNFRSF18 (GITR), BTLA and CD28. OncoPrint analysis in cBioPortal was performed to evaluate the expression and any possible genetic changes associated with these ICs in the tumors of CCA patients (n = 51).