CD274 and neoplasm: Similarly, GNB-derived EVs loaded with a PD-1 plasmid and coated with a tumor-targeting peptide induce the expression of PD-1 in tumor cells, promoting the inhibition of the PD-1/PD-L1 axis via a juxtracrine stimulus, and promoting the recruitment and activation of Tc cells and NK cells as well as the secretion of INF-γ [167], as seen in Figure 4.