The answer depends on which Apple CEO you're asking about. If you mean the current Apple CEO, then the answer is that Tim Cook is not publicly known to be married. If you mean the former Apple CEO Steve Jobs, the answer is Laurene Powell Jobs.
While Steve Jobs, the co-founder and former CEO of Apple Inc., was married to Laurene Powell Jobs, the current CEO, Tim Cook, has not publicly disclosed any marital status. Therefore, to provide a complete and accurate answer, we need to distinguish between the two scenarios.
Laurene Powell Jobs (Wife of former CEO, Steve Jobs)
Laurene Powell Jobs (born November 6, 1963) is an American billionaire businesswoman, executive, and philanthropist. She married Steve Jobs on March 18, 1991, and remained married to him until his death on October 5, 2011. She is the founder and chair of the Emerson Collective and XQ Institute. She also manages the Steve Jobs Trust.
Tim Cook (Current Apple CEO)
Tim Cook succeeded Steve Jobs as the CEO of Apple Inc. While he is a public figure, he maintains a level of privacy regarding his personal life. As of the current date, there is no publicly available information confirming that Tim Cook is married.
In summary, while Steve Jobs was married to Laurene Powell Jobs, Tim Cook is not publicly known to be married.