PDCD1 and hepatocellular carcinoma: Present immunotherapy agents like programmed cell death protein 1 (PD-1) blockade regulate the cytotoxic T lymphocytes to attack tumor cells, which are increasingly explored in nano strategies for HCC therapeutic strategies (Cancer Genome Atlas Research Network, 2017; Xu et al., 2019; Sangro et al., 2020; Zheng et al., 2020).