B cell lymphoma-derived exosomes upregulated inhibitory receptors PD-1 (programmed cell death protein 1), CTLA-4 (cytotoxic T lymphocyte-associated antigen-4) and BTLA (B- and T-lymphocyte attenuator), and induced apoptosis of T cells through activation of Fas/Fas ligand pathway (94). Here, PDCD1 is linked to B-cell non-Hodgkin lymphoma.