CD274 and neoplasm: Overall, the immune system acts as a modulator of the balance between activation, tolerance, and exhaustion of T cells and tumor pathology by a variety of molecules of coinhibition and costimulation, which are referred to as immune checkpoints (61, 62), such as PD-1 and PD-L1, the dysregulation of which may contribute to evasion of anticancer T-cell immunity (63).