OpenAI's Fidji Simo plans to step down from her role as a full-time executive after an extended medical leave. She will become a part-time adviser to the company. Her neuroimmune condition has worsened, and her road to recovery will take much longer than anticipated. Simo's product and business responsibilities will be divided among President Greg Brockman, CFO Sarah Friar, and Chief Strategy Officer Jason Kwon.