We present a case report of nivolumab-aggravated treatment-resistant chronic rhinosinusitis with nasal polyposis with asthma, suggestive of aspirin-exacerbated respiratory disease, normalized with the IL-5R antagonist benralizumab. For patients experiencing symptomatic complications of immunotherapy-associated eosinophilia, this case suggests anti-IL-5(R) biologics may durably resolve nasal polyposis and asthma symptoms, permitting continuity of checkpoint inhibitor therapy and sparing of systemic corticosteroids. Postulated mechanisms of checkpoint inhibition favoring eosinophilia and polyposis, and the uncertain effect of eosinophil reduction upon malignancy progression, are reviewed.