Moreover, we analyzed the differences in the levels of immune cell infiltration between the high- and low-CLDN18.2 expression groups in patients with STAD, which identified significant differences in various immune cells, such as CD8+ T cells, CD4+ memory T cells, CD4+ naive T cells, CD4+ T cells, and CD4+ Tcm cells. This evidence concerns the gene CD4 and gastric adenocarcinoma.