Cytokine Release Syndrome (CRS) is a potentially life-threatening condition that can occur as a result of certain treatments, such as chimeric antigen receptor (CAR) T-cell therapy. CRS is caused by an overactive immune response, resulting in the release of large amounts of cytokines into the bloodstream. Symptoms of CRS can include fever, chills, nausea, vomiting, rash, and difficulty breathing. Treatment for CRS typically involves supportive care and medications to reduce inflammation.