The aim of this study is to evaluate the efficacy of insulin‐like growth factor 1 receptor (IGF‐1R) inhibitor Linsitinib, in esophageal squamous cell carcinoma (ESCC), and to characterize special biomarker to screen Linsitinib‐sensitive patients as well as explore the molecular‐resistant mechanism to Linsitinib in ESCC. The gene discussed is IGF1R; the disease is esophageal squamous cell carcinoma.