CD274 and hepatocellular carcinoma: Through high-throughput small molecule screening, Pattenden et al. identified a series of HDAC inhibitors, such as SAHA,TSA,panobinostat (LBH-589),givinostat (ITF2357),abexinostat (PCI-24781),tubastatin A (HDAC6 selective), PCI-34051 (HDAC8 selective), and so on, which can remodel the chromatin accessibility.553 Yang et al. indicated that the HDAC8 inhibitor, PCI-34051, increased the infiltration of CD8+ T cells and enhanced the therapeutic effect of PD-L1 blockade in HCC mice model.132 Similarly, the HDAC6 inhibitor, tubastatin A, also inhibits the expression of PD-L1 in melanoma cells.