CD274 and Stroke: PD‐L1 is expressed on MSCs[26] and the PD‐1/PD‐L1 pathway mediates the immunosuppressive mechanism of MSCs.[27] Moreover, a previous study indicated massive production of inflammatory factors poststroke, transmigration of splenocytes to the circulation, and infiltration of ischemic areas of the brain by T cells, macrophages, and inflammatory polymorphonuclear cells, resulting in a worse stroke outcome.