As shown in Fig. 4c, CD8+ T cells (red) were mainly located in the space between tumor cells (green) in the FreeαPD1 & αPDL1-treated tumors, while most CD8+ T cells were closely associated with tumor cells in the imNAαPD1 & αPDL1-treated group (as indicated by the white arrows), which was accompanied by enhanced cytotoxicity against tumor cells (measured by the destruction of cell integrity). The gene discussed is CD8A; the disease is neoplasm.