Just days after he was ousted by the company he co-founded, former OpenAI CEO Sam Altman is joining Microsoft and so is another OpenAI co-founder, Greg Brockman.

The two men who helped bring ChatGPT to the world will lead Microsoft's new advanced AI research team.

So there's been a lot going on.

That's why I got CNN's Vanessa Jurkovich.

She's here with us now.

All right, Vanessa look, there are ongoing negotiations for Altman to return as OpenAI CEO, then he goes to Microsoft.

What's been happening here?

I don't think that ChatGPT could have written this drama.

This has been a lot in 72 hours.

So the breaking news that we have now is that 500 employees from OpenAI have sent this letter to the board, which ousted Sam Altman,

saying that if you do not resign, if you do not bring back Sam Altman, we will quit and we will join Sam Altman at Microsoft.

500 employees, that's most of the company.

But this all goes down on Friday when OpenAI basically pushes Sam Altman out the board, saying that he's not equipped to lead the company right now.

He hasn't been very transparent.

Behind the scenes, though, what we know is that there's a philosophical difference between Altman wanting to push AI forward and the board who wants to kind of dial the progress of AI back.

But what we know is that many employees have already followed Altman, including his co-founder Greg Brockman.

Over the weekend, we saw a photo of Altman at OpenAI's offices, maybe talks of bringing him back again.

That did not happen.

That's where you enter Microsoft.

They have invested $13 billion into OpenAI.

They own 49% of the company.

Just this morning, we're hearing that they have hired Altman to now run artificial intelligence at Microsoft.

And just moments ago, we heard from one of the board members who was part of that four person board that fired Altman.

And he says he actually regrets the fact that he's created all this chaos at OpenAI.

He's also one of the more than 500 people who has signed this open letter, calling for the board to resign, which means including himself.

This all matters because artificial intelligence is here.

It is the future.

There are serious conversations about whether or not it's moving too fast.

Can it be weaponized?

What does it mean for all of us?

There are so many businesses that rely on ChatGPT every single day.

I just want to read a quick quote from an analyst, Dan Ivers, who puts this perfectly.

I think he says, in a nutshell, "The J.V. four-person board at OpenAI was at the kids poker table and they thought they won until Nadella and Microsoft took this all over in a World Series game of poker move for the ages with the Valley and Wall Street watching.

This is going to continue to unfold over today, but just so much in 72 hours, changing the game of A.I.

So much has happened and I'm sure so much more.

Vanessa Jurkovich, thank you so much.

That is Stewart joins me from London.

Honestly, I mean, the fallout from the board decision could not be more consequential.

Some 500 of the 700 employees threatening to quit the company.

Just explain what's going on here and why this weekend's news was so significant.

It is hard to keep up with what has been one of the most spectacular corporate fallouts.

I think I can remember really in terms of a board firing a CEO very suddenly, seeing the fallout from investors, but also within the company, and this is just the latest.

This is a letter to the board of directors of OpenAI.

As you mentioned, over 500 employees have agreed to this.

And when I say it's the letter to the board of directors, Becky, there were six directors as of last week.

One was fired, Sam Altman.

The other co-founder, Greg Brockman, actually resigned on the basis of this news.

And a third is actually signing this letter.

So it was almost a letter to themselves at this stage, which means there are three directors are being very much targeted by this letter.

And I'll just highlight a few bits that we've had in the last hour.

It says they believe the board is incapable of overseeing OpenAI.

They say they may choose to resign and join Microsoft with Sam Altman and Greg Brockman, join that new entity. They be in a show. They have positions.

And these are their terms.

They say they will take the step imminently unless all current board members resign.

That's the three I mentioned.

And the board appoints two new lead independent directors.

They mentioned a couple and reinstate Sam Altman and Greg Brockman.

So that is the most extraordinary laying down of the law from over 500 employees.

The CTO and a board member on that as well.

So now you have to wonder, is the Microsoft move going to happen or are we going to see a complete rejig again at the top?

And are we going to see Sam Altman, Greg Brockman, going back to open?

Just a reminder for those who you know, for those you are in the kind of, you know, in the weeds of AI, they may not know who he is.

This guy is a very, very, very significant player, not just in business, but in US and global politics these days as well.

He's become the biggest voice, really, when we talk about artificial intelligence.

He's the loudest voice at least.

They're all just a handful of companies really running the AI debate I guess, in terms of a few companies that lead the way.

There's Google DeepMind with Demis Hassabis and the Sam Altman with OpenAI.

He is the biggest voice.

He's one of the co-founders of the company.

There are quite a few co-founders there, but he's become very vocal and very eloquent, particularly, as you mentioned, at Senate committee hearings and the political level.

You see him on the international stage, and he's very vocal on Twitter.

And one of the big questions for all of us, right on Friday was why has he been fired from the board?

And there's lots of speculation about this from the company.

We actually didn't get very much.

There was something about a lack of communication with the board, but no more detail.

Other people wonder whether his popularity had eclipsed the board, and therefore, frankly, they lost control of what some of them wanted to do with the company,

or whether his part in terms of trying to commercialize the profit part of OpenAI, because it is a nonprofit entity generally, whether they felt that was undermining or risking AI safety.

Where's he going?

Well, he signed up for Microsoft, but as of the last hour, this letter from over 500 employees demanding he goes back to OpenAI.

You have to wonder, Becky. Check back next hour.

Good stuff. Thanks.