Notably, in the tissue type classification, there were two pathological types of lung cancer, adenocarcinoma and squamous cell carcinoma, in which CCL17 high expression was strongly associated with good prognosis in adenocarcinoma (OS, HR = 0.77 (0.68–0.867), p = 4.9e-05; PFS, HR = 0.59 (0.43–0.82), p = 0.0012), while the relationship with the prognosis of squamous cell carcinoma was not significant (p > 0.05). Here, CCL17 is linked to squamous cell carcinoma.