The results showed that CNN1 expression was significantly correlated with CD4+ T, CD8+ T, and dendritic cells and macrophages and neutrophils in STAD (p < 0.01), which not only allowed us to see CNN1 as a relevant prognostic factor in a variety of tumors, such as GC, but also showcases the promise of CNN1 as a target for immunotherapy. This evidence concerns the gene CNN1 and gastric cancer.