CD274 and hepatocellular carcinoma: Chronic HBV infection commonly induces a tolerogenic microenvironment in the liver characterized by upregulation PDL-1 and IL-10 in Breg, increasing susceptibility of HBV-specific T cells to apoptosis induced by TIGIT+NKG2D+NK cells, limiting effective anti-tumor immunity.587 Highly suppressive PD-1hi Treg cells selectively enrich in HBV-related HCC and correlate with poor prognosis.588 In contrast, HCV evades immune surveillance by inducing dysfunctional CD8+ T cells and upregulating immune checkpoint proteins.