Microsoft will continue to use HERE Maps data but many questions remain | Windows Central
FWIW, Maps on W10M has turn by turn with voice and draws from the HERE database for its mapping. Yes you can download the same mapping data as HERE for offline nav with Maps. Also in W10M you can save maps to SD card.
You cannot download voicepacks to get a nav voice distinct from system voice.
You can import HERE Collections to Maps Favorites by using this tool on PC in a browser:
Maps Favorites Importer Our Blog has you covered with alternatives for W10M as well:
Check out these great alternatives to HERE Maps for Windows 10 Mobile | Windows Central
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