Furthermore, it has been shown that PD-1/PD-L1 exert an immunoregulatory action in different immune cells, such as T cells, B cells, natural killer (NK) cells, dendritic cells (DCs), and macrophages/microglia in MS and experimental autoimmune encephalomyelitis (EAE) models [75]. This evidence concerns the gene PDCD1 and myeloid sarcoma.