IFN-γ plays a beneficial role in the host defense of infectious diseases; however, it has adverse effects in the pathogenesis of autoimmune diseases, such as multiple sclerosis,1 systemic lupus erythematosus,2 type I diabetes,3etc. Although IFN-γ has been regarded as an important cytokine in immune surveillance during tumor development, accumulating evidence suggests that IFN-γ can also drive an immunosuppressive microenvironment to promote the immunoevasion of pathogens or cancer cells. This evidence concerns the gene IFNG and infectious disease.