CD4 and neoplasm: Remarkably, these CD4+ and CD8+ TIS-T populations also show a potent suppressive ability.15 We also demonstrated that tumor-induced senescence of T cells is triggered by soluble factors secreted by tumor cells and that this process can be prevented by IL-7.16 These data support the hypothesis that, within the tumor microenvironment, tumor-infiltrating T lymphocytes encounter tumor cells that promote their senescence and dysfunction.