in this review we discuss the most recent developments in gene editing technology and discuss their application to adoptive t cell immunotherapy engineered t cell therapies targeting cancer antigens have demonstrated significant efficacy in specific patient populations most impressively cd19 directed chimeric antigen receptor t cells cart19 have led to impressive responses in patients with b cell leukemia and lymphoma ctl019 or kymriah tisagenlecleucel a cd19 car t cell product developed by novartis and the university of pennsylvania was recently approved for clinical use by the food and drug administration representing a landmark in the application of adoptive t cell therapies as cart19 enters routine clinical use improving the efficacy of this exciting platform is the next step in broader application novel gene editing technologies like crispr cas9 allow facile editing of specific genes within the genome generating a powerful platform to further optimize the activity of engineered t cells.