The combination of programmed death receptor 1 (PD-1) inhibitors with chemotherapy has been recognized for the treatment of advanced and metastatic esophageal squamous cell carcinoma (ESCC). To the best of our knowledge, there is no published report to date which analyzes the efficacy and safety of this regimen in the treatment of locally primary-recurrent ESCC patients after definitive chemoradiotherapy or radiotherapy only. This is a prospective clinical study designed to enroll 79 patients. The study will focus on those who have attained a complete response (CR) subsequent to definitive chemoradiotherapy or radiotherapy and have a histologically proven in-field recurrence, with no distant metastases. These patients will receive treatment with a PD-1 inhibitor combined with monotherapy chemotherapy for 4 cycles, followed by a 2-year maintenance treatment with PD-1 inhibitors. During this period, patients diagnosed with esophageal wall thickening and identified as having progressive disease (PD) have the option to undergo salvage radiotherapy in conjunction with a dual-agent chemotherapy for 5 cycles. The primary endpoint of is 2-year after recurrence survival (ARS) rate. The secondary endpoints include the progression-free survival (PFS) and safety.