Ask HN: How are C. managers selected when opening office in another country?

I was always interested how the company decides on who to select for country manager, when opening an office in new country.

I've been a CEO of a small company, but from what I always heard from the talks and while networking, it always went more on how some of the people worked for the company at their main office before being tasked to go to another country as country managers.

However, I've noticed a lot of the people that became country managers in recent times, don't have any actual connection to the company beforehand. (Either knowing someone or having worked, collaborated with it)

And while I know the intricacies on running the company and managing it, this has always puzzled me.