Modify camera height after viewer.trackedEntity

I am studying Cesium and currently following this tutorial Build a Flight Tracker – Cesium Aircraft were displayed in Cesium.

I found that writing

Viewer. tracedEntity=airplaneEntity;

Afterwards, I want to adjust the camera height, but the following method is ineffective. How should I modify the camera height

Viewer.camera.setView

I hope to receive your help, God bless you