For example, the RING E3 ligase FBXO38 mediates the ubiquitination of PD-1, thereby regulating antitumor immunity in T cells (60).In hepatocellular carcinoma, RNF125 (RING type) directly ubiquitinates PD-L1 and maintains a stable protein level of PD-L1 (61). This evidence concerns the gene CD274 and hepatocellular carcinoma.