GZMK and immune system disorder: GO and KEGG analysis showed TRM, GZMK+ CD8+ T cells, and GNLY+ CD8+ T cells were mutually enriched in several functional categories, including T cell activation, response to interferon-gamma, response to tumor necrosis factor (GO analysis), and Th1 and Th2 cell differentiation, cell adhesion molecules, multiple immune diseases (KEGG analysis) (Fig. 5e).