CDK8-IN-4 is primarily used in research settings to study the role of cyclin-dependent kinase 8 (CDK8) in cellular processes. It is a selective inhibitor of CDK8, making it a valuable tool for investigating the kinase's involvement in transcriptional regulation, cell cycle control, and signal transduction pathways. Researchers utilize this compound to explore its potential in modulating CDK8 activity in diseases such as cancer, where CDK8 is often implicated in tumor progression and drug resistance. Additionally, CDK8-IN-4 helps in understanding the molecular mechanisms underlying CDK8's interaction with the mediator complex, providing insights into gene expression regulation. Its application extends to preclinical studies aimed at developing targeted therapies for CDK8-dependent disorders.