The comparative analysis between PCNSL and DLBCL suggests that PCNSL is more likely to be an immunologically deficient tumour, with a reduced number of T cells alongside M2 polarised macrophages, endothelin B receptor, HLA depletion, PD-L1, and T cell immunoglobulin, and a mucin-domain containing-3 (TIM-3) [142]. This evidence concerns the gene HAVCR2 and primary central nervous system lymphoma.