CD274 and neoplasm: In summary, these results suggest that CARPD-L1z T cells killed CARMSLNz T cells that upregulated PD-L1 expression upon activation by tumor cells in xenografts, this may be the reason why we failed to achieve a synergistic anti-tumor effect when combining CARMSLNz T with CARPD-L1z T or dPD1z T cells.