PDCD1 and hepatocellular carcinoma: Importantly, anti-PD-1 has been shown to have activity in mouse models of HCC that incorporate a fibrotic liver microenvironment and that replicate findings seen in human tumors such as progressively exhausted PD-1+ CD8+ T cells and accumulation of Tregs, as well as in patients with Child Pugh B liver dysfunction [22, 130].