CD19 and neoplasm: Bystander effects through the recruitment of immune effector cells, such as T cells, NK cells and macrophages in the tumor niche have been shown to significantly contribute to tumor control for instance in the CD19 CAR T cell trial ZUMA-1 (NCT02348216) (146) and in preclinical models (147) and shall be exploited using next generation CAR designs, engineered to inducibly express cytokines impacting on the cytokine milieu (148).