Take home message In this article, Duhen et al. identifies a new subset of CD8+ cells that are recruited and maintained within the tumor micro-environment. Using flow-cytometry and microarrays, they show that these tumor-infiltrating CD8 T cells have an exhaustion signature and have a Tissue-resident memory T (Trm) phenotype. Interestingly, these cells are also tumour-reactive and have a TCR repertoire capable of recognizing and killing autologous tumous cells. Of clinical relevance, they show that an increase frequency of these cells, at the time of operation, is correlated with a decrease risk of death in patients with head and neck squamous cell carcinoma. Importance The paper provides novel insight into the biology of tumor-infiltrating CD8+ T cells that could be harness for increase our fundamental knowledge of cancer biology, but that is also interesting for the development of novel therapeutic/diagnostic tools.