A recent study has demonstrated that while fully functional anti-CD19 CAR T cells are able to effectively kill tumor cells, the administration of anti-CD19 CAR T cells with a TRAIL inhibitor can suppress the cytotoxic effect of the CAR T cell [207], indicating the importance of TRAIL-mediated target cell killing as a key killing mechanism of CAR T cells. This evidence concerns the gene TNFSF10 and neoplasm.