CDK inhibitors are a class of drugs that target cyclin-dependent kinases (CDKs), which are essential for cell cycle regulation. By inhibiting these kinases, the drugs can slow down or stop the growth of cancer cells, making them a valuable option in cancer treatment. They are particularly effective in certain types of cancers, such as breast cancer, where they can be used alongside other therapies. These inhibitors work by disrupting the normal progression of the cell cycle, leading to cell cycle arrest and apoptosis (programmed cell death). Some well-known CDK inhibitors include palbociclib, ribociclib, and abemaciclib, which have shown promise in clinical trials and are now part of standard treatment regimens for specific cancers.