Combination therapy with ipilimumab and nivolumab is indicated for many types of cancers; however, several patients experience immune-related adverse events (irAEs). We herein report a case of cytokine release syndrome (CRS) in a 63-year-old woman with stage IV left clear cell renal cell carcinoma. Our patient developed CRS while taking prednisolone, 43 days after the start of ipilimumab and nivolumab administration. The patient was treated with steroid pulse therapy, which improved the symptoms of shock and respiratory failure. Increased vascular permeability and relative adrenal insufficiency are considered to be the main pathogeneses. The early administration of high-dose steroids is crucial as a replacement for corticosteroids.