Hi Apurupa, it all starts with your domainmodel. Once that is set up correctly, you hardly need a microflow to show a list of the department-employees to the department-manager.
So your domain model is probably something like this:
An employee is a person having the userrole she fullfills in the company. So one of the 2 userroles mentioned here: DepartmentManager and DepartmentStaff.
If you define the userroles in a way that the DepartmentManager can read (part of) the Employees (users having userroleDepartmentStaff) of the department she manages, you can drop in a dataview of a Department with a list of its employee and then the manager will only get to see what she is allowed to see.