https://youtu.be/0bNFkI_0jhc
Cloud service roles are made up of a collection of application and configuration files. Azure offers two different types of roles:

Web role: This role provides a dedicated IIS (Internet Information Services) web server for the automatic deployment and hosting of front-end websites.
Worker responsibilities: These roles enable the applications hosted within them to run asynchronously for longer periods of time, are independent of user interactions, and do not typically use IIS. They are also excellent for background processes. The applications are run independently.