IFNG and neoplasm: CD56brightCD16− NKs (considered less mature NKs) account for 5–10% of circulating NKs and act both as distant killers and regulatory cells, by producing TNFα and IFNγ (Figure 1D), which can exert direct anti-tumor activity, or can activate other effector cells of both innate and adaptive (T cell mediated) immunity [26].