CD274 and cholangiocarcinoma: Overexpression of PD-L1 was significantly associated with worse overall survival (OS) (HR = 1.58, 95%CI = 1.30 − 1.92, p < 0.001) but not with poor disease-free survival (DFS) (HR = 1.03, 95%CI = 0.68 − 1.55, p = 0.895) in CCA.