Although concurrent chemoradiotherapy (CRT) is recommended as standard of care in patients with locally advanced, unresectable, stage III non-small cell lung cancer (NSCLC), many patients who refuse or are not eligible for chemotherapy received radiotherapy (RT) alone with 5-year overall survival (OS) rate of about 5-6%. Immune-checkpoint inhibitors have demonstrated objective antitumor responses in patients with advanced NSCLC, but it is unclear how these agents can be used in the curative therapy with concurrent radiation. We report three cases of stage III unresectable NSCLC patients who refused chemotherapy received radiation and pembrolizumab immunotherapy. All patients had no local-regional recurrence with acceptable tolerance.