PRES (posterior reversible encephalopathy syndrome) is a clinical-radiographic syndrome comprising clinical symptoms, including headache, vision abnormalities, nausea/vomiting, seizures, and posterior cerebral white matter edema seen as radiographic changes. Commonly, PRES is known to occur with severely elevated blood pressure, or eclampsia. However, in recent times, increasing cases of PRES have been observed in patients being treated with immunotherapy or chemotherapy. Nivolumab is an immunotherapy used in the treatment of various cancers and is an increasingly identified cause of PRES. A few case reports exist in the literature. We report a case of nivolumab-induced PRES.