If you are looking to get all crm users based on the teamid then this post is for you. You can use below code to retrieve users:

private EntityCollection GetAllTeamUsers(IOrganizationService _CrmService,Guid TeamID)
{
//Create query expression
QueryExpression _Query = new QueryExpression();
_Query.EntityName = "systemuser";
_Query.ColumnSet = new ColumnSet(true);
_Query.ColumnSet.AddColumn("systemuserid");
_Query.LinkEntities.Add(new LinkEntity
{
LinkFromEntityName = "systemuser",
LinkToEntityName = "teammembership",
LinkFromAttributeName = "systemuserid",
LinkToAttributeName = "systemuserid",
LinkCriteria =
new FilterExpression
{
Conditions ={
new ConditionExpression("teamid",ConditionOperator.Equal,TeamID)
}
}
});
return _CrmService.RetrieveMultiple(_Query);
}

Enjoy !!!