PDCD1 and plasma cell myeloma: This study, as expected, showed that DC vaccination combined to the lenalidomide and PD-1 blockade regiment further inhibited MM tumor growth, consequently prolonging the survival of tumor-bearing mice: the triple combination induced strong anti-myeloma CTL responses and increased the number of effector cells (CD4+ T cells, CD8+ T cells, NK cells, and M1 macrophages), while effectively discouraging suppressor cells (MDSCs, Tregs, and M2 macrophages) in the systemic immune compartment.