Tim Cook celebrates his fifth anniversary as chief executive of Apple (AAPL)on Wednesday amid growth concerns over its key revenue driver – the iPhone.

While its flagship handset might be Apple's cash cow today, the next few years are likely to see the company explore other areas for growth.

CNBC highlights five areas where Apple is looking to invest in the next five years.

Cook has never confirmed that Apple is working on a car but speculation is rife that "Project Titan" is in the works.

Last month, the Wall Street Journal reported that the self-driving electric car project had a new boss.

And Apple also invested $1 billion in Chinese ride-hailing service Didi Chuxing in May, with commentators suggesting that this could be a way for the U.S. tech giant to get automotive expertize on board.

While a car may be some years off, the potential market could be lucrative.

"If they can come up with an electric car that would be priced reasonably and have many of the features and driver comforts that Tesla has for example, I think it would sell really well. The potential market is huge, there are hundreds of millions of cars sold at high prices," Walter Price, senior portfolio manager at Allianz Technology Trust, told CNBC in a TV interview on Wednesday.

Health has been a big focus for Apple in the past two years. In 2014, the company released a health app as well as a developer platform called HealthKit. The idea was to allow developers to make health apps that integrate with Apple's own app.

A key part is being able to collect people's data such as heart rate or even lab results to create a whole picture about a user's health. Early last year, hospitals were reportedly trialing Apple's health technology.

Cook has said the opportunity in health is "enormous" and the Apple Watch could be part of that. Analysts believe that Apple has an advantage in health because it has a wearable product with advanced sensors, a large install base of iPhone users to sell too, and it has a strong track record in controlling its own hardware and software.

"They have been strong on software and hardware combinations. To deliver a great health experience you need to combine software and services with hardware so it ties together," Ian Fogg, head of mobile at analysis firm IHS, told CNBC by phone on Wednesday.

In a recent interview with the Washington Post, Cook said augmented reality (AR) is a "core" technology and something that the company is "doing a lot of things" with behind the scenes.

AR is a new area that has been propelled by the success of Nintendo's "Pokemon Go" which uses the technology. It involves overlaying digital images over the real world environment.

Siri, Apple's digital personal assistant, is its most consumer-facing piece of artificial intelligence (AI). The term is very wide and could encompass anything from smarter predictive text to full blown automated systems that can run themselves.

For Apple, Siri has been at the forefront of its AI efforts, as it looks to create a voice-controlled assistant that can do things on your behalf. This could open up new areas for the company.

"The prediction of Siri is going way up," Cook said in a Washington Post interview.

Apple has been acquisitive in the AI space, recently buying Turi, a machine learning start-up, and Emotient, an AI company that can recognize facial expressions.

Apple has made a big push into the entertainment industry, launching Apple Music last year, and investing in content.

It has secured exclusive album and track releases on Apple Music and recently bought the rights to popular TV series "Carpool Karaoke".

The Cupertino, California-based firm also has Apple TV, but has yet to turn that into an all-you-can-eat streaming service like Netflix, something that analysts said was being blocked by broadcasters.

"The problem with the Apple TV is that the cable companies in the United States don't want to cede the consumer to Apple," Price said.

Still, this could be a potential area for growth if Apple continues to spend money on content.

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