Elon Musk and OpenAI CEO Sam Altman, once allies, no longer see eye to eye. Here's why.

The relationship between Elon Musk and OpenAI has taken an increasingly acrimonious — and public — turn, with the one-time allies lobbing allegations at each other as they battle over the future of artificial intelligence. 

For many observers, it may seem a surprising twist in a relationship that stems from at least 2015, when Musk helped found OpenAI on the premise that it would use its generative AI technology to benefit the public. 

But that relationship blew up publicly last week when Musk filed a lawsuit against OpenAI and two of its executives, CEO Sam Altman and President Greg Brockman, accusing them of violating those founding principles by putting profits over humanity.