CTLA4 and neoplasm: reported that WNT, SHH, and a subset of Group 4 medulloblastomas present higher myeloid cells infiltration in the tumor and identified an immunosuppressive environment in Group 3 and a subset of Group 4 medulloblastomas as mediated by anti-inflammatory cytokines and immune checkpoints such as TGFβ1, PD-L1, and CTLA4, yet, PD-L1 was absent from their sample analysis (55).