Because efficacy of T-BsAb is correlated to the total number of T cells and intratumoral T cells infiltration particularly of CD8+ T cells56, we investigated the BM niche CD8+ T cells to leukemic cells ratio over time in the MLL-AF9 leukemia model without treatment, and found that the ratio sharply decreased during AML progression with only 1 CD8+ T cell out of 250 leukemic cells at day 17 post-leukemia induction (Fig. 6G). Here, CD8A is linked to acute myeloid leukemia.