PDCD1 and hepatocellular carcinoma: In recent years, the systemic treatment of ICIs based on programmed cell death protein 1 (PD-1)/programmed cell death receptor ligand 1 (PD-L1) combined with targeted drugs and various local therapies has made noteworthy progress in advanced HCC patients (Anwanwan et al. 2020; Greten et al. 2019).