PDCD1 and diffuse large B-cell lymphoma: For instance, a high proportion of programmed cell death protein 1 (PD1) + CD8+ T cells and programmed cell death-ligand 1 (PD-L1) + T cells in the TME was found to predict poor survival in DLBCL, whereas high expression of immune checkpoint cytotoxic T-lymphocyte-associated protein 4 (CTLA4) on T cells might be associated with favorable outcome (Xu-Monette et al., 2019).