Dec 12 2018 09:11 AM
Although I do not work for Microsoft, I am an MVP and if I was going to try to join Microsoft's development team that build Microsoft Teams, this is what I would do to get in the door:
1. Go to hackathons, build events, etc.
2. Contribute to the GitHub repository for Teams training
3. Volunteer at Teams related community events
4. Start blogging or YouTubing content you have created
5. Get to know people by networking and showing your work so it will get noticed
6. Have a social media presence to promote your creations.
I hope this helps!