CEACAM5 and squamous cell carcinoma: Patients with PD-L1 expression in NSCLC often exhibit certain clinicopathological characteristics, including male sex, current smoking status, elevated PET-CT SUVmax, increased CEA levels, squamous cell carcinoma (SCC) type, spread through air spaces (STAS), TP53 mutations, advanced pathological stages, poor cellular differentiation, and the micropapillary/solid subtype in adenocarcinoma (ADC).