The anti-tumor role of γδ T cells was first established by the seminal work of Hayday and his colleagues using TCRδ-deficient mice.53 Early studies suggested that γδ T cells serve as an early source of IFNγ and contribute to anti-tumor responses in various cancer types.295–299 However, recent advancements have unveiled that γδ T cells can also play pro-tumor roles in cancer. This evidence concerns the gene IFNG and cancer.