John Ternus's biggest challenges as Apple's new CEO

John Ternus takes over as Apple ( AAPL ) CEO today, marking the end of Tim Cook's time in the role and the start of a new era for one of the world's most valuable companies.

Cook isn't exactly riding off into the sunset; he's sticking around as chair of Apple's board. But Ternus will be the one steering the company toward the future.

Cook casts a rather large shadow over Apple. He grew the company's market capitalization from $350 billion to more than $4 trillion over the 15 years he served as its chief executive. Now it's up to Ternus to ensure that growth continues. But he'll have to deliver on more than just that.

Ternus faces a number of challenges that will define Apple's path for years to come. That includes ramping up the company's AI efforts, managing its relationship with the Trump administration, contending with changing government regulations across the globe, and figuring out its next major product beyond the iPhone.

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Ternus will get to work rather quickly, with Apple set to host its annual iPhone event in early September. The company is widely expected to debut its iPhone 18 line, as well as its first foldable iPhone.

If it's a success, the foldable will give Ternus an early win as CEO, even if it was developed under Cook's tenure. During that same event, we'll also get a closer look at Apple's generative AI-powered Siri , a major test of the company's AI efforts.

Apple has taken heat in the past for not being as quick to adopt AI as its Big Tech peers. It announced an updated version of Siri at its WWDC event in 2024, but has repeatedly delayed its release due to technical and behind-the-scenes issues.

If the new Siri lives up to expectations, it would show Apple is finally making headway on AI.

"AI is going to start getting embedded more deeply across all devices, and I think that that is something that is going to be Turnus' thing," BofA Global Research analyst Wamsi Mohan told Yahoo Finance.

Part of that also means getting Apple's AI capabilities off the ground in both Europe and China , where the company has faced pushback due to regional regulations.

Ternus will also be tasked with maintaining Apple's relationship with the Trump administration. Cook proved to be a master politician, placating the administration when it called for the company to move iPhone manufacturing to America with large investments in its US-based ecosystem.

Trump has also said Cook has called him personally to address certain issues in the past. The outgoing CEO will still serve as Apple's chair, meaning he could remain the company's voice in Washington, but as Apple's new CEO, Ternus will still need to get used to the role of political operator.