Peninsula is the sequel (kind of) to Train To Busan. It's probably better to say that they take place in the same universe.
So let's start at the top. Even though horror fans will generally watch anything of any quality it's still tough to get folks to watch a foreign film. How about this, if you EVERY plan on watching a foreign horror film, start with Train To Busan. It is simply my favorite zombie movie EVER in any language from any country. Train To Busan accomplished everything and more that World War Z attempted and failed miserably to do (go read the book on that one, it bears little resemblance to the movie). It's a zombie movie with some emotional depth, a big budget, and swarming zombies.
Now comes Peninsula which looks like it takes it predecessor and mixes in some Fast & Furious and Mad Max action. It looks big, fun, and scary. I doubt my local multiplex will book this film, but I'll be first in line with some bucks when it hits on-demand. Check out the new trailer followed by the original one.