Kong et al. showed in immunophenotypic analyses of AML patients that high PD-1/TIM-3 expression on CD8+ T-cells was strongly associated with T-cell exhaustion and relapse post allo-HCT, whereby PD-1/TIM-3 positive T-cells of PB were already detected 2 months before clinical relapse, suggesting a predictive value of this observation [54]. The gene discussed is CD8A; the disease is acute myeloid leukemia.