Abstract: Esophageal cancer is one of the leading causes of cancer-related mortality in China, and esophageal squamous cell carcinoma (ESCC) is the predominant histological subtype. Most people are diagnosed with ESCC at an advanced stage and are thus ineligible for surgical resection. The current therapeutic options for unresectable locally advanced ESCC are limited. The risks of recurrence and metastasis are high after first-line treatment, such as with definitive concurrent chemoradiotherapy (dCCRT). Recent advances in targeted therapies and immune checkpoint inhibitors (ICIs) have expanded the clinical treatment options for ESCC. However, no consensus has been reached on whether maintenance therapy provides survival benefits or which maintenance strategies should be prioritized. We provide a systematic review of the progress of research on postprimary maintenance therapy for patients with unresectable locally advanced ESCC, with the goal of optimizing comprehensive treatment strategies and providing information for personalized therapeutic decision making.