GZMB and myelodysplastic syndrome: The expression of perforin and granzyme B in CD8+ T cells from NC co‐cultured with MDSCs from MDS patients (n = 9, samples: 038‐046) was lower than that of CD8+ T cells from NC that were cultured alone (perforin: 16.02 ± 5.86% vs 22.02 ± 5.96%, P = .0271*; granzyme B: 20.1% (14.08%‐37.12%) vs 31.68% (24.17%‐42.32%), P = .0605) (Figure 2A,B).