Although human γδ T cells rarely produce IL‐17, several groups have reported an elevated frequency of IL‐17+ γδ T (γδT17) cells in response to a combination of Th17‐polarising cytokines IL‐1β, IL‐6, IL‐23 and TGF‐β in some disease settings.24, 39 Many of these cytokines are elevated in the tumor microenvironment of certain cancers, and indeed, there have been some reports of IL‐17‐producing γδ T cells having a pro‐tumor role in various human malignancies. Here, IL17A is linked to cancer.