These two are the main elements in web hosting service: cPanel and Plesk that allow users to manage their website.
Plesk is the extension based architecture that permits fast delivery of new features. For example, new advisor, extension catalogue, WordPress toolkit, etc.
It is flexible and allows running both the software: Linux and Plesk.
Where as cPanel is developed as a dedicated or virtual server. It leverages a three-tier structure that involves capabilities for administrators, reseller, management of the website and server.
Linux only allows the control panel. It supports CentOS, Cloud Linux, etc.