CX3CR1 and glioblastoma: Even though CX3CR1+ CD8+ T cells might not be specific to GBM, as they are found in healthy donor and different inflammation related conditions (Böttcher et al., 2015; Gerlach et al., 2016; Yamauchi et al., 2021; Yan et al., 2018), the absence of these effector and potentially ICI therapy responsive CD8+ T cells in the glioma TME could serve as an additional explanation for the disappointing outcome of clinical trials using ICI in glioma patients.