Microsoft has invested time and resources into perfecting its services and app offerings on Android. This includes Cortana, which rivals Google's own assistant. It's actually rather easy to switch to Cortana and rely on Microsoft's assistant while enjoying Google's mobile OS. A discussion is well underway on our forum on which is better and why.
Community member davidewart asked the question: Should he replace Google Assistant with Cortana on Android?
I use Cortana on my OnePlus 5, but I enjoy Google's solution more, especially while in Android Auto mode. Both are certainly capable assistants, but Google has the edge with more integration and functions. Still, Microsoft is working hard to improve services on Android, and connectivity with Windows 10 is only going to get better. It's easy to switch between the two to see which you prefer on your smartphone. And you don't really need to only use one. But what do you think?