The biggest challenge for us is simply the time zone difference. There is nearly very little time where the US team's working hours and the India team's working hours overlap. The only way to have face-to-face time is if people from one country start work really early and one country stay working rather late.
This means that something like a code review can be delayed a long time. If two team members are working at the same time, the review might take an hour or two. If the review is between India/US team members the same review can take 3-4 days in the best case: (1. code, 2. review, 3. address review, 4. approve)
So really we're looking for projects for the teams that can be done independently with as little cross-country review as possible but this is tricky for our project's current state of development.
I guess the takeaways would be: Look for roles in countries that have working hours with overlap with your own. A remote team doesn't necessarily mean any timezone
Look for roles with larger companies. If a large company does remote, it's probably more likely that they would have a team with similar hours to your own.