These miR‐34a‐enriched exosomes stimulated CD8+ T cell activation by reducing the expression of immune evasion markers, such as PD‐L1, in the tumor microenvironment, leading to an increased CD8+/CD4+ T cell ratio and enhancing anti‐tumor immune responses in vivo.[113] In another study, nanovaccine was developed using exosomes derived from immunogenically dying PANC‐02 PCa cells, engineered with MART‐1 peptides on the surface and loaded with CCL22 siRNA through electroporation. Here, CCL22 is linked to neoplasm.