HDAC1 and neoplasm: Also, the newly designed HDAC1/2/6 inhibitor SDFZ‐8 not only effectively upregulates PD‐L1 expression in tumor cells but also modulates lymphocyte expression of PD‐1 and PD‐L1, thereby alleviating the suppressive immune microenvironment and enhancing the therapeutic efficacy of anti‐PD‐L1 blockade.