Garon EB, et al. - Researchers report the effectiveness as well as safety of pembrolizumab monotherapy in patients with non–small-cell lung cancer (NSCLC) as assessed over long-term follow-up (5 years) with participants from the phase Ib KEYNOTE-001 study. The treatment regimen used was intravenous pembrolizumab 2 mg/kg every 3 weeks or 10 mg/kg every 2 or 3 weeks. In patients with treatment-naive or previously treated advanced NSCLC, durable antitumor activity and high 5-year overall survival (OS) rates were seen with pembrolizumab monotherapy. Those with a programmed death ligand 1 tumor proportion score of 50% or greater had 5-year OS rate over 25%. A tolerable long-term safety profile was displayed by pembrolizumab, with little proof of late-onset or new toxicity.