try to understand which component the movement is referring to

In the third person template character blueprint, what is the component that mouseinput is affecting. If it refers to the whole actor which contains a collision and movement component, when move the mouse, the whole thing including camera and mesh should be rotated together, so the camera is still facing the back of the mesh, but in the actual game, it seems only the camera is rotated so we are able to see the face of the character. This confuses me. What exactly the rotation or movement applies to?

Hello,
If, in third person character blueprint, you select third person character in components, you can see in details / pawn : use controller rotation pitch /yaw /roll. If you check one, mesh and camera will move on mouse move. If you uncheck, only camera will move.

that explains. Thanks a lot.