Notably, expanded CD8+ effector/memory (Teff/mem) and exhausted (Tex) T cells in TB lungs show elevated expression of cytotoxic granule GzmK, IFN-γ and TNF, suggesting heightened inflammatory and cytotoxic activity [64,66], while other cytotoxic granules (e.g., GzmM) and activation-related transcripts (e.g., S100A4, S100A6) are downregulated in both CD8+ and CD4+ Teff/mem cells [66]. Here, CD4 is linked to tuberculosis.