It was previously reported that tumor cells in hematological malignancies, such as multiple myeloma (MM) [37–39], non-Hodgkin lymphoma (NHL) [40], classic Hodgkin lymphoma (HL) [41], and myelodysplastic syndrome (MDS) [42, 43], can escape from the host immune system through immune checkpoints pathways, such as cytotoxic T-lymphocyte associated protein-4 (CTLA-4) and programed-death 1 (PD-1) pathways. Here, CTLA4 is linked to plasma cell myeloma.