TNFRSF9 and neoplasm: The functional status of TNFRSF9+ CD8+ T cells might partly result from the complicated interactions among immune cells (helper T cells, CD8+ T cells, and myeloid cells) within the tumor, and high enrichment of TNFRSF9+ CD8+ T cells could be a predictor of immunotherapy and a novel therapeutic target in mRCC [79].