PDCD1 and neoplasm: Equipping CD19 CAR-T cells with IL-12 retained a central memory-effector phenotype with increased anti-tumor efficacy in vitro while IL-15 armed CD19 CAR-T cells had increased cell expansion, reduce cell death rate, decrease expression of PD-1 and improved anti-tumor effects in vivo compared to unarmored CD19 CAR-T cells [89].