Immune checkpoint inhibitors are a type of medicine used to treat some cancers, including metastatic melanoma, renal clear cell carcinoma, non-Hodgkin lymphoma, non-small cell lung cancer and other solid organ tumours. Checkpoint inhibitors include ipilimumab, nivolumab and pembrolizumab. People taking checkpoint inhibitors may have a higher risk of immune-related side effects following influenza vaccination. Talk to your oncologist about the risks and benefits of the flu shot.