In parallel with gradually elevated extracellular lactate levels in B16, MC38 and 4T1 tumor tissues (LAhigh tumor; Extended Data Fig. 1a), intracellular lactate ions in tumor-infiltrating CD8+ T cells correspondingly increased (Extended Data Fig. 1b), concomitant with the cytosolic acidification (Extended Data Fig. 1c,d). The gene discussed is CD8A; the disease is neoplasm.