FLT3 and acute myeloid leukemia: High expression of PD-1, PD-L1, and T-cell immunoglobulin mucin domain 3 (TIM3) and co-expression of PD-1/CTLA-4, PD-1/PD-L1, PD-1/LAG-3, and PD-L2/CTLA-4 are associated with poor prognosis in AML, particularly in patients with FLT3, RUNX1, and TET2 mutations [75,76,77].