ICOS and neoplasm: For example, ICOS+ tumor‐infiltrating lymphocytes (TIL) remarkably increased in advanced gastric cancer and represent poor prognosis11; ICIs combined with ICOS agonist GSK3359609 could exert better antitumor effects by enhancing T‐cell cytotoxicity in head and neck squamous cell carcinoma (clinical trial information: NCT04128696).