CRS is one of the major side effects of CAR‐T cell therapy because when CAR‐T cells exert their effector functions, large amounts of cytokines, such as IL‐6, IFN‐γ, IL‐1β, GM‐CSF and TNF‐α production, cause a systemic inflammatory response, leading to signs such as hypoxia, fever, myalgia, hypotension and neurologic dysfunction, which threaten patients' lives.101, 102. The gene discussed is IL6; the disease is congenital rubella syndrome.