BACKGROUND: Nivolumab is an anti-PD1 immune checkpoint inhibitor commonly used for the treatment of solid organ and hematological malignancies. Severe infusion reaction due to nivolumab is quite rare. CASE: We report a case of severe infusion reaction due to nivolumab necessitating ICU admission and withdrawal of further nivolumab use in a patient with metastatic non-small cell lung cancer. CONCLUSION: Our knowledge and expertise with the use of immune checkpoint inhibitors are still evolving. This report highlights one of the rare possible side-effects that clinicians and patients may have to face with increasing indications and use of nivolumab in day to day practice.