Very Detailed Explanation About Min Role in below. https://technet.microsoft.com/en-us/library/mt346114(v=office.16).aspx

MinRole is a new farm topology based on a set of predefined server roles introduced in SharePoint Server 2016. When configuring your SharePoint farm, you now select the role of a server when you create a new farm or join a server to an existing farm. SharePoint will automatically configure the services on each server based on the server's role. SharePoint Server 2016 has been optimized for the MinRole farm topology.