KIR2DL1 and esophageal squamous cell carcinoma: To analyze the correlation between the inducing effect of Fusobacterium nucleatum (Fn) on the surface expression of the inhibitory receptor KIR2DL1 on CD8+ T cells in oesophageal squamous cell carcinoma (ESCC) and the clinicopathological features and survival prognosis and to explore its clinical significance.