In this compelling video, hematologist-oncologist David L. Porter, MD, describes the development at the renowned Abramson Cancer Center of treatments for refractory chronic and acute lymphocytic leukemia involving genetically modified autologous T cells carrying chimeric antigen receptors (CAR) for the B lymphocyte antigen CD19. Dr. Porter reviews the clinical trials, documents the dramatic outcomes in patients with CLL and ALL arising from CAR T cell immunotherapy, and offers insight into the future of the therapy.