You may have thought that janitor and cleaner are the same, but there is a slight difference in their role. A cleaner focuses on the cleaning work, and in a commercial setting, usually works in a team. Cleaners work in various environments and mostly on tasks like dusting, vacuuming, mopping, disinfecting, etc.
On the other hand, janitorial services usually consider complete maintenance and cleaning of a building, while janitors do a combination of different tasks. For example, janitors are responsible for managing the functionality of the building, making small repairs, groundskeeping, but also cleaning and maintenance.