This case report suggested that increased ACTH is an early indicator of the hypophysitis onset.[5] We here present the case of a patient with renal cell cancer who received nivolumab and ipilimumab combination therapy and developed thyroid dysfunction initially and was then hospitalized due to fulminant hypophysitis following diabetic ketoacidosis caused by the onset of fulminant type 1 diabetes (T1D). Here, POMC is linked to type 1 diabetes mellitus.