Permission for one user's ToDo to other user


How to give access of one employee ToDo to another employee?

Two employees, employee A, employee B under the Same company.

employee B is reporting to employee A.

Now I wanted to show All ToDo, Attendance, Leave Application of employee B to employee A.

Attendance and Leave Application can be shown by writing employee A name in Reports To of employee B.

But for ToDo I don’t have any Idea, How can I achieve this by using Roles and Permission manager?