In addition, certain pathogens, tumors, and leukemias use the expression of ICM to evade the T-cell response (immune escape) [16–18]. In adult sepsis, increased expression of ICM, especially of expression of the PD-1/programmed death ligand 1 (PD-L1) axis, was correlated with the risk to develop nosocomial infections [19] and blockage of the PD-1/PD-L1 axis resulted in increased survival in experimental sepsis [20] [21]. Here, PDCD1 is linked to leukemia.