Most sites offering "Black Ops II for free" are not authorized by Activision. Downloading from these sources usually carries significant risks:

Since it’s an older title, you can often find used physical discs for PC or console at very low prices on sites like eBay or local used-game shops.

Pirating copyrighted software is illegal and can lead to issues with your Internet Service Provider (ISP).

Even years after its release, Black Ops II is considered one of the best in the franchise because of its branching storyline, the introduction of the "Pick 10" system in multiplayer, and the iconic Origins and Mob of the Dead Zombie maps. Playing a legitimate version ensures you have access to the official servers and a community that is still active today.

Sites like Humble Bundle or Green Man Gaming often offer legitimate Steam keys at a discount.