Do you have country (field) information in your data source? If yes then use that field on label
The Country name which you're seeing is generated from open street map layers. That you cannot bring on top of your data (marks).
While you can't bring the labels from the map forward, you have at least a couple of choices.
- You could reduce the opacity of the colors enough so that they can be seen through.
- You can drag a field either from the data source or a calculated field to Text
- You could create second axis that has nothing on it but the country names and have that as the right hand of the dual axis map.
- You could put the names into Tooltips so that pop up when hovered over.
- You could create a viz in the tooltip that shows the map without the colors.