Guerriero et al22 found that Class IIa HDAC inhibitor TMP195 can promote macrophages towards an anti‐tumor phenotype with enhanced capacity to activate cytotoxic T lymphocytes by regulating its gene expression in mouse model of breast cancer, combining TMP195 with PD‐1 inhibitor can significantly enhance the durability of tumor reduction. The gene discussed is PDCD1; the disease is neoplasm.