Catalyzes the ATP-dependent phosphorylation of cellobiose to produce cellobiose-6'-P. May have a dual role of kinase and transcriptional regulator of the cellobiose-PTS operon. ATP + D-cellobiose = 6-phospho-beta-D-glucosyl-(1->4)-D-glucose + ADP + H(+) Belongs to the ROK (NagC/XylR) family.