Notably, regarding tumor location, high PD-L1 expression was a prognostic factor for patients with eCCA (HR = 1.71, 95%CI = 1.25 − 2.36, p < 0.001) and CCA including iCCA and eCCA (HR = 1.98, 95%CI = 1.47 − 2.65, p < 0.001). The gene discussed is CD274; the disease is cholangiocarcinoma.