INS and metastatic melanoma: A 42-year-old male with metastatic melanoma treated with nivolumab and ipilimumab for three cycles presented to the emergency room with nausea, vomiting, and diarrhea. Blood tests showed serum glucose to be elevated at 728 mg/dL (40.4 mmol/L), bicarbonate of 14 mmol/L, and an elevated anion gap of 25 mmol/L. The patient was treated with intravenous insulin bolus and drip with IV fluids. The patient was diagnosed with DKA.