In some cases, switching between multiple basemap layers is useful while viewing and editing the data of a map in ArcGIS Pro. However, attempting to add a new basemap layer using the Basemap button, updates the current layer instead of adding a layer to the map.
The newly added World Imagery basemap layer updates the previous Basemap.
The following are two possible solutions to add multiple basemap layers to a map in an ArcGIS Pro project, adding layers from the Living Atlas, and adding layers from ArcGIS Online. In these workflows, only one basemap layer is added at a time. Repeat the steps to add multiple basemap layers as needed.
Add basemap layers from the Living Atlas content in ArcGIS Pro
Note: While majority of the items in the Living Atlas are free, some items are considered subscriber and premium content.
Add basemap layers from ArcGIS Online to ArcGIS Pro
Note: Drag the newly added basemap layer to the bottom of the Drawing Order in Pro, so the basemap does not hinder viewing and editing.