Currently, deficient mismatch repair/microsatellite instability-high (dMMR/MSI-H), tumor mutation burden-high (TMB-H) and PD-L1 expression have been widely studied as biomarkers related to response to immunotherapy in solid tumors (15–17), but the evidence in CCA is insufficient (11, 12, 14, 18, 19). Here, CD274 is linked to cholangiocarcinoma.