Recent trials, including TOPAZ-1 and KEYNOTE-966, have shown that combining standard first-line chemotherapy with immune checkpoint inhibitors (ICIs) targeting programmed cell death protein-1 (PD-1) or programmed death-ligand 1 (PD-L1) can enhance survival in patients with untreated metastatic or unresectable CCA (5–7). The gene discussed is PDCD1; the disease is cholangiocarcinoma.