Cyclin-dependent kinase (CDK) 7 has a unique functional repertoire by virtue of its dual role in transcription and cell cycle progression. Whereas CDK7 is ubiquitously expressed in various types of cancer, its downregulation leads to reduced cell proliferation. Importantly, it is now agreed that targeting transcription selectively limits the synthesis of mRNAs involved in tumor growth without causing an outage of transcription of housekeeping genes. Thus, CDK7 has been considered as a viable therapeutic target in cancer. Indeed, the development of CDK7 inhibitors has gained huge momentum with two molecules, CT7001 and SY-1365, currently under clinical development. Herein, we discuss the latest understanding of the role of CDK7 in cancer cells and provide an overview of the pharmacophores of CDK7 inhibitors, their efficacy in various cancer models, and their clinical development.