CCR8 and glioblastoma: In the tumor microenvironment of glioblastoma (GBM), C–C motif chemokine receptor 8 (CCR8) expression mediated by H3K18la in regulatory T (Treg) cells contributes to the immunosuppressive tumor microenvironment to impede chimeric antigen receptor-T (CAR-T) cell immunotherapy (Fig. 2d)46.