They demonstrated that PD-1 inhibitor-related sclerosing cholangitis can be divided into three groups: (I) extrahepatic type, diffuse extrahepatic biliary hypertrophy without biliary stenosis; (II) intrahepatic type, multiple stenoses, especially in the intrahepatic bile duct, without extrahepatic biliary hypertrophy; and (III) diffuse type, diffuse biliary tract hypertrophy with multiple stenoses of the intrahepatic and extrahepatic bile ducts. The gene discussed is PDCD1; the disease is sclerosing cholangitis.