All in all, the existing evidence suggests a mostly positive correlation between CLDN18.2 expression and the presence of certain immune cells, such as CD8+ T cells, CD4+ effector T cells, neutrophils, and cancer-associated fibroblasts, whereas correlations with other cell types like macrophages and NK cells, as well as the PD-L1 expression, remain inconsistent and require further clarification. The gene discussed is CLDN18; the disease is cancer.