CD8A and melanoma: Similarly, for melanoma patients with no reaction to immunization therapy, exosomal PD-L1 derived from melanoma cells was shown to interfere with the antitumor activity of immune cells by binding to CD8+ T cells, inhibiting the proliferation of tumor-infiltrating CD8+ T lymphocytes (TILs) and reducing the production of IFN-γ and IL-2 [62].