Apple's new CEO, John Ternus, takes over from Tim Cook at a pivotal time for the company

Apple's new CEO John Ternus takes the helm of the iconic tech giant on Tuesday, ending Tim Cook's 15-year tenure during which the company's value skyrocket to $4.6 trillion thanks to the iPhone's enormous popularity.

The transition to a new CEO comes at a pivotal time for Apple. Artificial intelligence has unleashed the greatest upheaval within the industry since Steve Jobs unveiled the first iPhone in 2007. Apple has gotten off to a rough start in AI after stumbling in its efforts to deliver new features built on the technology, as promised nearly two years ago.

Earlier this year, it unveiled new artificial intelligence advances, including upgrades to its Siri assistant, emphasizing a focus on privacy and day-to-day use as the iPhone maker tries to catch up with rivals.

Ternus faces challenges that will force him to step outside his comfort zone in hardware engineering. Beyond finding ways to keep Apple competitive in the artificial intelligence race, he will need to navigate supply chain questions and relationships with figures such as President Donald Trump, who offered public praise for his predecessor on Tuesday.

Serving as Apple CEO will also require soft skills, including developing relationships with important figures. Cook cultivated ties with Trump as he navigated the company through business challenges, including Trump's trade and tariff war targeting countries in Asia, where Apple has extensive manufacturing supply chains. Although he is handing over the CEO reins at Apple, Cook is widely expected to help the company maintain a good relationship with Trump after he shifts to his new role as executive chairman.

Ternus worked on some of Apple's signature products under Cook, including the Apple Watch, AirPods and Apple Vision Pro. He will headline next week's launch of the latest iPhone at Apple's Cupertino, California, headquarters.