BACKGROUND: Nivolumab, an immune checkpoint inhibitor is used to treat advanced metastatic malignancies. Data showed that nivolumab can cause exacerbated response of T-Helper 2 cells and lead to airway inflammation. OBJECTIVE: To present the upper airway findings of a 69-year-old woman after treatment with nivolumab. METHODS: Case report. RESULTS: A 69-year old woman with no history of chronic rhinosinusitis developed complaints of nasal congestion, rhinorrhea, sneezing, and anosmia. These symptoms started after one year of treatment with nivolumab. Pale polyps were observed on fiberoptic endoscopy examination. A gradual increase in eosinophil blood counts was noted. On histopathology, heavy infiltrates of eosinophils were seen in the tissue. CONCLUSIONS: Nivolumab is used to treat various advanced metastatic malignancies, with a good safety profile. Nevertheless, physicians must be alert to the possibility of evolving type II inflammation in patients, as appropriate therapy can be provided to improve their quality of life.