PDCD1 and central nervous system cancer: Additionally, neoadjuvant ICIs, including PD-1 inibitors nivolumab and pembrolizumab, could reshape the tumor immune microenvironment and enhance the immune response in glioblastoma (Cloughesy et al., 2019; Schalper et al., 2019), suggesting that the tumor immune microenvironment in glioma could be shifted to be more susceptible to immunotherapy.