Fidji Simo steps down permanently
Fidji Simo will not return full-time from medical leave and will instead become a part-time adviser to OpenAI.
Her condition had worsened and recovery would take longer than expected.
The change is the latest in a string of executive shifts at OpenAI ahead of a possible IPO this year.
Simo had been widely tipped to take a larger leadership role once OpenAI went public