I have been migrating to the new Cesium releases for several years. I just migrated to 1.72 and see the following console message
BingMapsApi.defaultKey is deprecated and will be removed in CesiumJS 1.73. Pass your access token directly to the BingMapsGeocoderService or BingMapsImageryProvider constructors.
Are you adding the Bing geocoder, or imagery directly to your viewer (using one of those classes mentioned in the console message)? If so, each has a constructor option where you can pass your access token, see https://cesium.com/docs/cesiumjs-ref-doc/BingMapsImageryProvider.html?classFilter=Imager.
That was way too easy.
I started use:
imageryProvider : Cesium.createWorldImagery
rather than Bing. It seems, for example that the AERIAL views are the same. It there are situation where Bing would be a preferred choice?
createWorldImagery function is just a shorthand for Bing imagery right now (
Cesium.IonResource.fromAssetId(2)), in the same way that
Cesium.createWorldTerrain is a shorthand for