CD8A and lung cancer: In lung cancer, high GBP5 indicates potential sensitivity to immune checkpoint blockers like PD-L1 inhibitors, driven by immune cell infiltration (e.g., CD8+ T cells, NK cells), measurable in respiratory tissues, bronchoalveolar lavage, or blood samples via flow cytometry, qPCR, or single-cell RNA sequencing, providing a robust predictive tool [59].