It is a Chinese/American fantasy war film that presents the idea that The Great Wall of China was built to keep out monsters from devouring humanity. It stars Matt Damon, Willem Dafoe, Pedro Pascal and Andy Lau. The film was directed by Yimou Zhang. Below are screenshots from the trailer, which just dropped on IMDb. Here is the link: http://www.imdb.com/title/tt2034800/
The film is expected to open in the states on February 17, 2017.