LILRB1 and cancer: Also, given different binding specificity of HLA-G between ILT-2 and ILT-4 resulted from its extracellular structure, that ILT-2 binds HLA-G1 and HLA-G5 while ILT-4 binds HLA-G1, -G2, -G4, -G5, and HLA-G6 isoforms, the landscape of HLA-G isoforms and their degree of expression in cancers can tremendously affect the benefits of HLA-G/ILTs based cancer immunotherapy.