Cemiplimab, a fully human monoclonal PD-1 antibody, is approved in the USA and Europe as monotherapy in adults for the first-line treatment of NSCLC expressing programmed cell death-ligand 1 (PD-L1) in ≥50% of tumor cells with no epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), or ROS proto-oncogene 1 (ROS1) aberrations, where the patient has locally advanced disease but is not a candidate for definitive chemoradiation therapy, or has metastases. The gene discussed is ALK; the disease is neoplasm.