Esophageal squamous cell carcinoma (ESCC) remains a highly lethal cancer worldwide, largely due to late diagnosis. Current screening methods such as upper endoscopy are invasive, operator-dependent, and limited in their ability to detect early-stage lesions. To address this clinical need, the SYNERGY study seeks to develop a non-invasive, blood-based biomarker assay that integrates cell-free microRNAs (cf-miRNAs) and exosomal microRNAs (exo-miRNAs) to detect ESCC at an early and potentially curable stage. This multicenter translational study includes discovery, training, and validation phases using preoperative plasma or serum samples. By combining the tumor specificity of exosomal miRNAs with the systemic sensitivity of cf-miRNAs, SYNERGY aims to construct a robust diagnostic model with high sensitivity and specificity for early ESCC detection.