S100A1 and lung cancer: Firstly, determining the plasma S100A1 levels of patients with tumor, especially those with lung cancer, is currently not as specific or definitive for immunotherapy efficacy as PD-L1, MHC, and TMB are.55 The relationships between plasma S100A1 expression and clinicopathological parameters have not yet been thoroughly investigated, which can present limitations in terms of consistency and reliability across diverse populations, environments, or conditions.