From Apple’s press release:

Apple® today announced that the App Store℠ has added UnionPay as a payment option for customers in China. China UnionPay is the most popular payment card in China and will provide App Store customers with a simple and more convenient way to purchase their favorite apps. Customers can easily link their Apple ID with a UnionPay debit or credit card for one-tap purchases.

“The ability to buy apps and make purchases using UnionPay cards has been one of the most requested features from our customers in China,” said Eddy Cue, Apple’s senior vice president of Internet Software and Services. “China is already our second largest market for app downloads, and now we’re providing users with an incredibly convenient way to purchase their favorite apps with just one-tap.”

From the Wall Street Journal:

The UnionPay partnership could potentially open the door for Apple Pay in China, if Apple can strike agreements with popular retailers and overcome technical and regulatory hurdles. Another route for Apple is a possible alliance with Alibaba, China’s largest e-commerce company, whose payment affiliate Alipay is the country’s largest mobile payment processor.