CDK4 and cancer: TQB3616, a novel CDK4/6 inhibitor, exhibits high selectivity and effectiveness in preclinical cancer models.1048 SPH3643, a highly selective CDK4/6 inhibitor, can efficiently and stably cross the blood‐brain barrier.1049 Dalpiciclib (SHR6390), a novel, highly selective CDK4/6 inhibitor, reveals high activity with IC50 of 12.4 nM and 9.9 nM against CDK4 and CDK6, respectively.1050 Flavopiridol, a pan-CDK inhibitor originally purified from Dysoxylum binectariferum,1051 is the first CDK inhibitor entering clinical trials and can target CDK1, CDK2, CDK4, CDK6, and CDK7.1052