CD274 and neoplasm: Programmed death-Ligand 1 (PD-L1) expression is upregulated in tumor cells or antigen-presenting cells, and evades immune surveillance after binding to programmed death 1 (PD-1) on the surface of tumor-infiltrating immune cells.518,519 RelB promotes prostate cancer immune evasion by expanding PD-L1/PD-1-mediated immune checkpoints to suppress T-cell immunity.520 TNF-α inhibits ubiquitinated degradation of PD-L1 via p65-induced COP9 signalosome 5 (CSN5), leading to immune escape.521 Immunotherapy resistance is an area of concern.