If NK cell activation by MHC I deficient cancer cells is weak or the balance of inhibitory signals is high, leading to anergy and exhaustion of NK cells, then activation by cytokines such as IL-18 and IL-12 may restore their activation.114 However, licensed NK cells in an MHC I sufficient environment will be inhibited, especially without activation or with increased inhibition from cancer cells. Here, IL18 is linked to cancer.