China's market for movies is expanding at an insane rate. Over the course of roughly a decade, the country's box office sales have grown almost twice as fast as their economy at large, and in 2017 movie sales in China are expected to outnumber those in the US. This is due, in no small part, to the country's rapidly growing middle class. An estimated 76 percent of China's urban population will be considered middle class by 2022.
So, Hollywood has an obvious financial incentive to appeal to a Chinese audience. But large production companies also have to consider whether their film will actually make it into Chinese theaters.
An international quota system sets a cap on the number of foreign films that can screen in the country each year. In 2016 it was just 34. And although there are no official rules outlining what kind of movies the government will accept, it's pretty much assumed that anything critical of China won't make the cut.
Hollywood Reporter: China Box Office Flatlines in 2016
Business Insider: 18 Hollywood movies that pandered to China's giant box office