Combining CTLA-4 and PD-1 inhibitors could have a synergistic antitumor effect, resulting in enhanced activity and increased infiltration of tumor-infiltrating lymphocytes (TILs) as well as a decrease in regulatory T cells (Tregs) in the CCA microenvironment [26,27] (Table 2). The gene discussed is CTLA4; the disease is cholangiocarcinoma.