The interaction between PD-L1 expressed in tumor cells and PD-1 expressed in T cells inhibits the activity of effector T cells and increases the secretion of proinflammatory cytokines, such as tumor necrosis factor (TNF)-alpha, interleukin (IL)-2, and interferon-gamma (IFN-γ) [13]. The gene discussed is IFNG; the disease is neoplasm.