Research has shown that high PD-L1 expression can be detected in occupational cholangiocarcinoma (cholangiocarcinoma caused by occupational exposure to organic solvents), suggesting that the critical mechanism for forming occupational cholangiocarcinoma may be related to the immune escape of the PD-1/PD-L1 pathway [9]. The gene discussed is PDCD1; the disease is cholangiocarcinoma.