CTLA4 and central nervous system cancer: The development of immune targets, including programmed cell death 1 (PD1), cytotoxic T lymphocyte-associated protein 4 (CTLA4), and killer cell lectin-like receptor subfamily B member 1 (KLRB1) (Litak et al., 2019; Mathewson et al., 2021), lays the groundwork for further tumor-free treatment of glioma.