HDAC9 and melanoma: The effects of HDAC inhibitors include increasing the amounts and cytotoxicity of NK and CD8+ T cells and modulating of Foxp3+ infiltration.36 HDAC inhibitors can increase the presentation of tumor-associated antigens and activity of immune-related pathways, resulting in an enhanced antitumor response of T cells.37 According to preclinical studies, HDAC inhibitors also upregulate the expression of the immune checkpoints in melanoma.38