Time Machine is the system level backup service that's built into macOS. It works transparently, behind the scenes, to take snapshots of your files. Backups are implicit but you have little control over what is backed up, when they are backed up and where the backups are placed. ChronoSync provides explicit control over your backups allowing you to control what is backed up, where it is placed and how often it is backed up. ChronoSync actually works quite complimentary with Time Machine. For more details, click here.