PDCD1 and hepatocellular carcinoma: It could be seen that (i) in HBV-specific T cells, the expression of PD-1 was induced with the increase of HBsAg content; (ii) the expression of CTLA-4 and TIM-3 was upregulated in HBsAg_medium group, but lower than that in HBV-high group; (iii) TOX showed high specificity to HBV-associated HCC (Fig. 5B and C).