CTLA4 and non-small cell lung carcinoma: Ipilimumab, a fully humanized monoclonal antibody that directly inhibits the function of the immune checkpoint inhibitor CTLA-4, has been shown to improve survival in patients with metastatic cancers.[1] Nivolumab, which targets the immune checkpoint inhibitor PD-1, has also been used in various cancers including non-small-cell lung cancer (NSCLC).