HDAC6 and melanoma: Histone deacetylase 6 (HDAC6) has been identified in the activation of STAT3 and upregulation of PD-L1 in melanoma.37,38 H3K4me3 can be catalyzed a promote PD-L1 transcription in pancreatic cancer and melanoma.39–41 At the level of RNA regulation, inflammatory signalling, aberrant oncogenic signalling and indirect regulation by miRNA are summarized.