Downloading files from unofficial sources carries significant risks that you should consider before proceeding:
: Be extremely cautious of websites offering a "Call of Duty: Black Ops 2 APK + OBB" that claims to be a native Android app. These are often malicious files or "fake" versions intended to deliver malware.
Double-check that the OBB file size matches the download (usually 4.2GB to 4.8GB). Then, launch the game from your app drawer. If done correctly, you should bypass the download screen and go straight to the offline menu.