CTLA4 and hepatocellular carcinoma: However, since 2017, two immune checkpoint inhibitors targeting the programmed cell death-1 (PD-1) pathway, pembrolizumab and nivolumab, the latter alone or in combination with the monoclonal antibody targeting cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA-4) have been FDA-approved as second-line treatment for advanced HCC (7–9).