20 risk factors comprised: advanced age, male sex, smoking status, preexisting interstitial lung abnormalities, pulmonary fibrosis, COPD, thoracic radiotherapy history, squamous cell carcinoma histology (versus adenocarcinoma), early-stage NSCLC (Stage III versus IV), multifocal metastases (≥2 sites), PD-1 inhibitors (versus PD-L1 agents), elevated PD-L1 expression (≥50%), pembrolizumab use (versus nivolumab), AEC, CRP, PLR, WBC, and hypoalbuminemia. Here, CRP is linked to squamous cell carcinoma.