(Marcio Jose Sanchez/AP)

Apple's $1 billion investment in Chinese ride-hailing startup Didi Chuxing means the two will be working closely together, said Didi's president Jean Liu on a conference call with reporters.

Just what exactly it will be helping Didi with is still very unclear.

"We are very confident that we will benefit each other on product, on technology, and on many other levels," Liu said.

The deal came together after the Didi Chuxing executive team visited Tim Cook at Apple headquarters in Cupertino on April 20. The $1 billion investment closed "like lightning" only a few short weeks later.

When asked if Didi Chuxing will be helping with Apple's soured relationship with the Chinese government, Liu only responded that they can help each other.

"The policy makers in China now have been more and more open now," Liu said. "There’s a good foundation that we can help each other in many ways."

In an interview with Reuters, Apple CEO Tim Cook positioned this investment as a way to grow its presence in China.

"We are making the investment for a number of strategic reasons, including a chance to learn more about certain segments of the China market," Cook told Reuters.

The strategic part of the investment could be to get a leg up on other competitors like Uber on self-driving car technology. Apple has long been rumored to be working on an Apple car, and Didi Chuxing hasn't said whether or not it's actively working on self-driving technology now. Instead, Liu said, the company is building a technology platform that is designed to work with any partners.

"We’re big believers in autonomous driving and we believe technology is the solution," Liu said. "We can work with different partners on autonomous driving, and it is technology neutral."

The investment gives Apple a strong foothold into the Chinese market. Didi is currently operating in more than 400 cities in China, and breaking even in 200 of them. There are more than 14 million registered drivers on the platform, and the company completes 11 million rides a day, Liu said. But, there's still room to grow, and that's where she is hoping Apple may help.

"When you look at the penetration, it’s only 1% in China, even though its 11 million rides," Liu said. "How do we get to much higher penetration?"

Didi is rumored to be raising funds at $25 billion valuation, according to a Wall Street Journal article from April. Apple's investment is part of an ongoing round for the company.

"It’s oversubscribed. Much more demand than we originally planned for," Liu said, without commenting on exactly how much had been committed.