PDCD1 and neoplasm: Given that LAG-3 and PD-1 are co-expressed on both CD4+ and CD8+ TILs and co-blockade of the LAG-3 and PD-1 pathways has been shown to improve anti-tumor CD8+ T cell responses [64,66], it warrants further investigation whether the dual blockade of PD-1 and LAG-3 in CAR-T cells can enhance the efficacy of CAR-T cells.