TNF and neoplasm: As has previously been shown, Tim‐3‐ and PD‐1‐expressing exhausted CD8+ T cells in chronic viral infections and tumor microenvironments are dysfunctional, as indicated by their loss of IFN‐γ and TNF‐α (Barber et al., 2006; Jin et al., 2010; Sakuishi et al., 2010).