CDK/HDAC-IN-4 is a highly selective dual inhibitor of cyclin-dependent kinase (CDK) and histone deacetylase (HDAC), with IC50 values of 88.4 nM and 168.9 nM, respectively. This compound exhibits antiproliferative effects in both hematologic and solid tumor cells. Additionally, CDK/HDAC-IN-4 induces apoptosis and S-phase cell cycle arrest in MV-4-11 cells. It has also demonstrated significant antitumor efficacy in an MV-4-11 xenograft model.