CDK5 and breast cancer: Dinaciclib is a potent and selective inhibitor of cyclin‐dependent kinase (CDK) that acts on CDK2, CDK5, CDK1 and CDK9, with clinical efficacy and safety in chronic lymphocytic leukemia, which is currently under phase III trial.[20, 21] The combination regimes based on dinaciclib are carried out in multiple malignant tumors: dinaciclib and veliparib for advanced solid tumors (phase I, NCT01434316), dinaciclib and venetoclax for relapsed or refractory acute myeloid leukemia (phase I, NCT03484520), dinaciclib and pembrolizumab for advanced breast cancer (phase I, NCT01676753).