Recent multispectral imaging analyses in human GBM have also revealed that macrophages are the most abundant immune population, followed by T cells and neutrophils, with NK and NKT cells being comparatively rare, and identified novel immunosuppressive subsets such as PD1+ NK cells, PD1+CD8+ T cells, and PDL1+ neutrophils (54, 55). Here, PDCD1 is linked to glioblastoma.