IntroductionAggressive T‐cell lymphomas continue to have a poor prognosis. There are over 30 different subtypes of peripheral T‐cell lymphoma (PTCL), and we are now beginning to understand the differences between the various subtypes beyond histologic variations.Molecular Pathogenesis of Various Subtypes of PTCLGene expression profiling and other molecular techniques have enabled deeper understanding of differences in various subtypes as reflected in the latest 5th WHO classification of PTCL. It is becoming increasingly clear that therapeutic approaches that target specific cellular pathways are needed to improve the clinical outcomes of PTCL.Targeted TherapiesThere are many targeted agents currently in various stages of clinical trials for PTCL that take advantage of the differential expression of specific proteins or receptors in PTCL tumors. This includes the CD30 directed antibody drug conjugate brentuximab vedotin. Other notable targets are phosphatidylinositol 3‐kinase inhibitors, histone deacetylase inhibitors, CD25, and chemokine receptor 4. Anaplastic lymphoma kinase (ALK) inhibitors are promising for ALK expressing tumors.ImmunotherapiesAllogeneic stem cell transplant continues to be the curative therapy for most aggressive subtypes of PTCL. The use of checkpoint inhibitors in the treatment of PTCL is still controversial, with best results seen in cases of extranodal natural killer cell/T‐cell lymphoma. Bispecific antibody‐based treatments and chimeric antigen receptor cell‐based therapies are in clinical trials.