Recently, scRNA‐seq studies are supported with other techniques including mass cytometry (cytometry by time‐of‐flight, CyTOF) where for example both studies confirmed that regulatory T cells (T‐reg) in the tumour express higher levels of tumour necrosis factor receptor superfamily member 9 (TNFRSF9; encoding 4‐1BB), inducible T cell co‐stimulator (ICOS) and cytotoxic T lymphocyte‐associated antigen 4 (CTLA4) than T‐reg cells in blood or adjacent normal tissue, possibly reflective of an activated state.97 This evidence concerns the gene TNFRSF9 and neoplasm.