Abstract: Owing to the insidious onset and limited awareness of early screening, many patients with esophageal squamous cell carcinoma (ESCC) are diagnosed at an advanced stage. Immunochemotherapy is the current standard first-line treatment for advanced ESCC; however, survival outcomes remain suboptimal. Radiotherapy, with its precise local control and potential immunomodulatory effects, is anticipated to act synergistically with immunochemotherapy, offering a novel direction for overcoming survival limitations. This review systematically summarizes the progress in the use of radiotherapy as a first-line treatment for advanced ESCC and discusses the synergistic mechanisms, clinical applications, and challenges associated with its combination with immunochemotherapy.