Improved clinical outcomes have been achieved for a number of solid and hematological diseases treated with immune checkpoint blockade (ICB) targeting cytotoxic T lymphocyte associated protein (CTLA)-4 and programmed cell death 1 (PD-1) or its ligand PD-L1 [1,2,3,4,5,6,7,8,9,10,11]. The gene discussed is PDCD1; the disease is hematologic disorder.