A recent study found that PD-1+TIM-3+ Vδ2 T cells, PD-L1, and HMGB1 were significantly higher in AML patients than in healthy controls, suggesting that PD-1 alone is insufficient to indicate functional impairment, and Vδ2 T cells may require anti-TIM-3 inhibition for functional revival [157]. Here, PDCD1 is linked to acute myeloid leukemia.