Notably, upon long-term in vitro ↑[H+] exposure, the frequency of TIM-3+LAG-3+ infiltrating OT-I T cells and CD19-CAR T cells within the tumors was largely reduced after adoptive transfer (Fig. 6c–e and Extended Data Fig. 10b), which is consistent with their lower exhaustion in vitro and improved tumor control capacity in vivo. Here, CD19 is linked to neoplasm.