Tumour‐infiltrating CD8+ T cells can be found in different states, including effector cytotoxic CD8+ T cells that express granzyme B (Gzmb) and perforin (Prf1), and stem‐like TCF1+ CD8+ T cells that lack effector functions but can replenish the cytotoxic CD8+ T cell pool [33]. This evidence concerns the gene PRF1 and neoplasm.