What is the largest current video game by file size?

[EloKa]

I think ARK Survival Evolved reaches over 200 GB on PC with all the DLC.
Add mods from the Steam Workshop and you can easily pass the 300 GB mark.

 

[Ravelle]

Elder Scrolls Online is around 100+ I believe.

 

[Xwing]

File compression is a lost art form for some developers, especially on sound files. Sigh...