I am sure this is known already, but in case not...
Elon was part of the founding team for OpenAI as a non-profit organization to compete with Google, who was dominating the AI research field at the time. In 2018, OpenAI was having hard time getting enough fund to run its operations, and Elon made an attempt to absorb OpenAI under Tesla. The board did not agree with Elon and Elon has since left OpenAI.
Looks like this is an act II for Elon to take control of OpenAI, but it is going to be an uphill battle this time