HLA-C and neoplasm: They are able to stimulate antitumor immune response and modulate tumor cell proliferation.[78] The biologically active cargoes on exosomes, such as MHC and costimulatory molecules, have been shown to participate in exosome‐mediated anti‐cancer immune responses and could be employed as immunotherapeutic vaccines.[30] Exosomes derived from natural killer immune cells have a significant anti‐tumor effect.