Apple plans to expand its growing stable of services this year with "material" new additions, Apple CEO Tim Cook said Tuesday during an interview on CNBC.

"You will see us announce new services this year. There will more things coming," Cook told CNBC's Jim Cramer. "I believe they'll be material over time. I'm not going to forecast."

Apple has been working on the new services for "multiple years," Cook said, calling attention to the company's efforts in health care.

"This is an area that I believe, if you zoom out into the future, and you look back, and you ask the question, 'What was Apple's greatest contribution to mankind?' It will be about health," Cook said.

Apple has made a big push into the health and fitness industry, providing more health data to people through its devices, including step-counting on the iPhone and heart-rate tracking on the Apple Watch.

Cook said features like the ECG app on the Apple Watch Series 4, which monitor the electrical patterns of your heart rate and analyze them for potential health issues, are helping with "democratizing" health care.

"We are taking what has been with the institution and empowering the individual to manage their health. And we're just at the front end of this," he said. "But I do think, looking back, in the future, you will answer that question: Apple's most important contribution to mankind has been in health."

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