PDCD1 and hepatocellular carcinoma: An anti‐CTLA‐4 antibody (ipilimumab), an anti‐PD‐L1 antibody (atezolizumab), and two anti‐PD‐1 antibodies (nivolumab and pembrolizumab) have been approved by the FDA for combination therapy or monotherapy in patients with advanced HCC.8