Chimeric antigen receptor T cells (CAR T) and T cell receptor T cells (TCR T) are two major approaches in this category.[49, 50] CAR T was initially designed to recognize CD19, a marker commonly expressed on B cell leukemias and lymphomas.[51] Two of these genetically engineered cells (axicabtagene ciloleucel and tisagenlecleucel for lymphoma) have received FDA approval and are in clinical use. The gene discussed is CD19; the disease is lymphoma.