Alame M, Pirel M, Costes-Martineau V, et al. - Tumor tissue and clinical data from 57 primary central nervous system diffuse large B cell lymphoma (PCNS-DLBCL) and used immunohistochemistry were obtained to investigate tumor-associated macrophages (CD68, CD163), tumor-infiltrating lymphocytes (CD3, CD4, CD8, PD1) and tumor B cells (PAX5/PDL1 double stains, PDL1) in order characterize programmed cell death-1 (PD1)/programmed death-ligand 1 (PD-L1) immune checkpoints and the composition of the tumor microenvironment (TME) in PCNS-DLBCL. Findings established an important role of TME composition and PD1/PDL1 crosstalk in PCNS-DLBCL pathogenesis bringing new shrewdness to the targeted therapy of this aggressive lymphoma.