The results demonstrated that the gastric cancer microenvironment could be categorized into four distinct immune interaction patterns through analysis of the TCGA-STAD cohort: the “Immune Barrier Dominant” type (TME 1), the “Immune Barrier with CD8+ T Cell Exhaustion” type (TME 2), the “CD8+ T Cell Exhaustion Dominant” type (TME 4), and the “Immune Desert” type (TME 3). Here, CD8A is linked to gastric cancer.