PDCD1 and hepatocellular carcinoma: Recently, mounting studies have confirmed that several immune checkpoint inhibitors (ICIs), including targeting PD-L1 inhibitors (atezolizumab), CTLA-4 inhibitors (nivolumab), and PD-1 inhibitors (pembrolizumab), are revolutionizing the treatment approaches in HCC by leading to increased survival benefits and long-lasting antitumor responses.