1) In the absence of TIM-3 ligands, BAT3 binds the TIM-3 cytoplasmic tail and recruits the active form of LCK to the TCR complex to activate TCR signaling. 2) In the presence of ligand, BAT3 is released from the TIM-3 cytoplasmic tail, resulting in the recruitment of phosphatases, dephosphorylation of LCK, and inhibition of TCR signaling. Tyrosine kinase FYN can be recruited to the TIM-3 tail after the release of BAT3. 3) TIM-3 blockade may promote TIM-3-BAT3 interaction and TCR signaling.