A recent study reported that PD-L1 is overexpressed in occupational cholangiocarcinoma, a type of cholangiocarcinoma arising from occupational exposure to organic solvents, indicating that PD1/PD-L1 axis-dependent immune escape may be an important mechanism for formation of occupational cholangiocarcinoma 21. The gene discussed is PDCD1; the disease is cholangiocarcinoma.