IL10 and glioblastoma: HNSCC and GBM have an immunosuppressive microenvironment characterized by secretion of immunosuppressive cytokines (TGF-β, IL-10), loss or downregulation of MHC class-I and antigen processing machinery components, upregulation of immune-checkpoint molecules, dysfunctional T and natural killer (NK) cells, as well as recruitment of immunological suppressors, including regulatory T cells (Treg), myeloid-derived suppressor cells (MDSC), and tumor-associated macrophages (TAM).