Despite the fact that cancer cells cannot secrete INF-γ while NK, CD8+, and Th22 IFN-γ+CD4+ T cells, macrophages, IFN-producing killer dendritic cells (IKDC), and group 1 innate lymphoid cells (ILC1) secrete this cytokine in the tumor environment, complex cross-talk between cancer cells and IFN-γ-producing cells may promote immunosuppressive tumor microenvironments [16]. This evidence concerns the gene CD4 and cancer.