Therefore, given that the PD-1-blocking scFv secreted by CAR-T cells was able to bind to bystander cells, we hypothesize that local secretion of CD133-specific CAR-T cells secreting PD-1 blocking scFv cells in this study may protect endogenous antitumour immune cells and reduce the outgrowth of CD133-negative tumours. This evidence concerns the gene PDCD1 and neoplasm.