Case Presentation: A 70-year-old man treated with Nivolumab for metastatic melanoma, presented with mild nausea and vomiting for a few days. He denied a change in urine output or appearance of urine, flank pain, or difficulty urinating. Creatinine on admission was 8.9 mg/dl (baseline 0.8mg/dl). Urinalysis revealed mild proteinuria, 21-50 WBCs/hpf. Spot protein/creatinine ratio was [...]