Chidamide is primarily used in the treatment of certain types of cancer, particularly relapsed or refractory peripheral T-cell lymphoma (PTCL). It functions as a histone deacetylase (HDAC) inhibitor, which helps in regulating gene expression and inducing cancer cell death. By modifying the chromatin structure, it promotes the activation of tumor suppressor genes and inhibits the growth of malignant cells. This makes it a valuable option for patients who have not responded to conventional therapies. Additionally, its role in epigenetic regulation is being explored for potential applications in other hematologic malignancies and solid tumors, offering hope for expanded therapeutic uses in the future.