NavigationTemplate, MapTemplate not showing map

Hello everyone,
I am trying to make android auto navigation app with my existing navigation app.

Tried multiple templates provided by car app library but none of them loading the map. can anyone please help me to add map in app?
how to load map in android auto app? do we need to integrate google map for this? if yes, can anyone please let me know how we can integrate google map?

Start by reproducing the issue with the NavigationTemplate and MapTemplate in the Android Auto navigation sample. Check whether either template is expected to render map content and document the required map integration; done means the navigation app displays its map in Android Auto or clearly reports the missing prerequisite.

Written by the indexing model from the issue text.