TAM and microglia show high expression of CX3CR1 [132,208,209], whereas high CX3CL1 expression occurs in other cells [209], e.g., in GBM cells [147], especially in cells with IDH1-R132H mutation of the gene encoding isocitrate dehydrogenase 1 (IDH1) [78]. Here, CX3CL1 is linked to glioblastoma.