HLA-G and neoplasm: HLA-G engages with ILT2/4 and KIR2DL4 to elicit the suppression of immune effector cells, including cytotoxic T cells and natural killer (NK) cells, as well as the expansion of immunosuppressive cells like Treg cells and myeloid-derived suppressor cells (MDSCs), resulting in an immunosuppressive microenvironment and contributing to the immune escape of tumor cells [9].