Updating map to the latest map

Hi There!
I am new to cesium and also to Javascript

I want to know that how can we update the sandcastle cesium map to the latest map of today

I am using this
const viewer = new Cesium.Viewer(“cesiumContainer”, {
baseLayer: Cesium.ImageryLayer.fromProviderAsync(

but the ArcGis Map is like a couple of months old


This matter is actually unrelated to Cesium, depending on whether the data provided by the map service provider is the latest.