I don't really know, but I did read one article so I'm basically an expert.
OpenAI was founded by some dude named Altman.
The company grew to 700 or so employees and they have a board of directors.
That board removed Altman from the company for being "misleading" and Microsoft hired him like 10 minutes later. Microsoft was a large investor in OpenAI beforehand - so there was already a relationship there.
OpenAI employees wrote a letter to the board telling them they all needed to get fucked and bring back Altman, or they were all going to follow him to Microsoft and OpenAI would basically be up a creek without a paddle.
Please note - That's probably all completely wrong.
Also please note: This is when the computers become self-aware and take over.