PDCD1 and hepatocellular carcinoma: Furthermore, nivolumab, the anti-programmed cell death protein 1 (PD-1), has been proposed for the treatment of advanced HCC patients who have been treated with sorafenib (ID NCT02576509), and the combination of Ipilimumab, the anti-cytotoxic T-lymphocyte antigen 4 (CTLA-4), and nivolumab suggests an increased response rate for advanced HCC (ID NCT03510871).