Based on the GEO dataset, we found that the MHC Class II-related pathway and the CD8 T cell activation-related pathway were enriched in patients with low KLK8 expression and they were downregulated in patients with high KLK8 expression, indicating that low KLK8 expression might be associated with a more active immune microenvironment, which was favorable for tumor elimination. The gene discussed is CD8A; the disease is neoplasm.