Concurrent chemoradiotherapy is now considered to be the standard treatment modality for esophageal cancer patients who are medically unfit for surgery. However, elderly patients have limitations in their ability to tolerate concurrent chemoradiotherapy in comparison to nonelderly patients because of medical comorbidities and reduced functional reserve of organs. Immune checkpoint inhibitors, including PD-1 inhibitor, have been used in a large number of clinical studies on esophageal cancer and have achieved certain results. PD-1 inhibitor combined with radiotherapy may be a new strategy for elderly patients with esophageal cancer. This study aims to explore the efficacy and safety of PD-1 inhibitor combined with radiotherapy in the treatment of elderly patients with esophageal cancer. PD-1 inhibitor was delivered 200mg once before radiotherapy and 200mg every 3-4 weeks after radiotherapy for one year.