To ensure that a team named US Sales automatically contains all the users that have the department attribute set to Sales, you need to create a dynamic team based on Azure AD group dynamic membership rules. Here are the steps to follow:

Create a new team in Microsoft Teams as you would to create a normal team. Name it US Sales. If the team already exists, you can skip this step.

Sign in to the Azure portal with your admin credentials.

Go to Azure Active Directory > Groups. Find the group that corresponds to the US Sales team and select it.

On the group details page, select Properties on the left menu and change the membership type to Dynamic user. Click Save.

On the same page, select Dynamic membership rules on the left menu and add an expression that dynamically retrieves the users that have the department attribute set to Sales. In this case, the expression is user.department -eq "Sales". Click Save.

That’s it. You have successfully created a dynamic team for US Sales. This means that only users with the department attribute set to Sales will be added or removed from the team automatically. You can also modify the expression to include other criteria, such as location, job title, or manage