Hi,
when you split the viewport window into sevral viewports, you can have a diffrent view angle in each viewport (you can be in “top view” in one, while being in “front” and “side” views in other viewports).
This includes the fact that you can be in camera view in one of your viewports and out of camera view in others.
However, even if you have multiple cameras in your scene, you can only have one active camera in the whole scene at the time. That means that you can’t have two viewports, each in camera view but from diffrent cameras (if both viewports are in camera view, it will be from the same camera).