Additionally, ubiquitin-specific peptidase 22 (USP22) in HCC [141], ubiquitin-specific peptidase 9, X-linked (USP9X) in OSCC [142], and ubiquitin C-terminal hydrolase L1 (UCHL1) in NSCLC [143] deubiquitinate and upregulate the PD-L1 expression. This evidence concerns the gene USP9X and hepatocellular carcinoma.