Teams give you the ability to create groups of members with read, write, or admin permissions to repositories that belong to the organization. Teams are also central to many of GitHub's collaborative features, such as team @mentions to notify appropriate groups of people that you'd like to request their input or attention.
Improved organization permissions give organizations fine-grained permissions designed to make it easier to use teams, control organization-wide settings, and improve security.
People with owner or team maintainer roles can manage repository access with teams. Each team can have different repository access permissions.
The "Owner" is now an administrative role given to individual members of your organization. Members of your legacy Owners team are automatically given owner privileges.
Use teams to give specific read, write, or admin access to repositories. Teams can also let you create groups of members with similar interests for easier collaboration.
An organization owner can promote any member of the organization to team maintainer for a team, giving them a subset of privileges available to organization owners.