POSTN and esophageal squamous cell carcinoma: ESCC lymph node metastatic microenvironment picture shows that the emergence or expansion of interferon‐induced T/B cells, POSTN+ myofibroblast cells, APOC1+APOE+ macrophages and intercellular communications through ligand‐receptor to establish premetastatic niche and facilitate metastasis in a profoundly immunosuppressed TME.