The recent approval of belumosudil, a highly selective, low-molecular-weight ROCK2 inhibitor against chronic graft-versus-host disease [44] also indicates the multiple functional roles of ROCK2, although a recent study [45] suggested that the therapeutic effectiveness of belumosudil was partially due to inhibition of the protein kinase CK2α. This evidence concerns the gene ROCK2 and chronic graft versus host disease.