Explanation
User and team management is the area of Microsoft Dataverse where you can create and maintain user accounts and profiles.
A user is any person who works for a business unit who uses Dataverse. Each user has a user account.
A team is a group of users. Teams let users across an organization collaborate and share information.
Note: Why use Dataverse?
Easy to secure - Data is securely stored so that users can see it only if you grant them access. Role-based security allows you to control access to tables for different users within your organization.
Data from your Dynamics 365 applications is also stored within Dataverse, allowing you to quickly build apps that use your Dynamics 365 data and extend your apps with Power Apps.
Reference:
https://docs.microsoft.com/en-us/powerapps/developer/data-platform/user-team-entities
https://docs.microsoft.com/en-us/powerapps/maker/data-platform/data-platform-intro