CTLA4 and hepatocellular carcinoma: In the last few decades, great progress has been made in the understanding of HCC biology and immunotherapy, but the therapeutic effects of anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA4) and anti-PD-1 immunotherapy remain unsatisfactory (Sangro et al., 2013; El-Khoueiry et al., 2017; Zhu et al., 2018).