To evaluate the potential relationship between neutrophil defensin 1, 2 and 3 and the anti-PD-(L)1 immunotherapy response in NSCLC patients, peptidomic profiling was performed on pretreatment formalin-fixed paraffin-embedded (FFPE) biopsies of NSCLC patients who received immunotherapy. This evidence concerns the gene DEFA1 and non-small cell lung carcinoma.