Preliminary data from our lab indicate that BMSC, another major protumoral component in the BM niche of MGUS and MM patients, are PD-L1+, further confirming that there is a redundancy of immune suppressor cells exploiting the ICP/ICP-L circuitry to hamper myeloma cell recognition and elimination by immune effector cells in the TME. Here, CD274 is linked to plasma cell myeloma.