The treatment of patients with non-small cell lung cancer (NSCLC)1 has been revolutionised by the emergence of immune-checkpoint inhibitors or ‘immune modulators’ (IMs), particularly those targeted against tumours exploiting the PD-1/PD-L1 (programmed death-1; programme death ligand-1) checkpoint as a mechanism of immune escape. The gene discussed is CD274; the disease is non-small cell lung carcinoma.