Cakewalk created Sonar, Cakewalk closed, Sonar was put on a (Gibson) shelf.
Bandlab bought Sonar from Gibson, re-branded it "Cakewalk by Bandlab", made it available again.
Bandlab will continue development of the software (now called Cakewalk), so while your old Sonar will continue to work, if you want new additions and/or bug fixes you switch to the re-branded version.