As a primary inducer of PD-L1 expression18,31, IFN-γ was detected at the interface of PD-L1+ tumors and tumor infiltrating lymphocytes (TIL), suggesting that TILs trigger their own inhibition by secreting cytokines such as IFN-γ that drive tumor PD-L1 expression46. The gene discussed is IFNG; the disease is neoplasm.