HDAC6 and neoplasm: In addition, NextA, a selective HDAC6 inhibitor, was found to increase the proportion of M1/M2 macrophages in tumor microenvironments, promoting IFN-γ and IL-2 levels and transformation of tumor microenvironments from “cold” to “hot”, thus enhancing the efficacy of immune checkpoint blocking therapy (Knox et al., 2019b).