Go to one of the trusted sites above. Look for the link labeled:

The game is a third-person shooter known for its meta-humor and frequent fourth-wall breaks.

PC game, you should be extremely cautious. Here is the "solid story" on why these downloads can be risky and what the actual situation is for the game today: The "Highly Compressed" Trap Malware Risk

Below is a draft blog post explaining why the game is gone, the risks of "highly compressed" downloads, and the few remaining ways to play. Why Can’t I Find the Deadpool Game Online?

To download the Deadpool PC game, you'll need to visit a reputable online platform that offers the game for download. Some popular options include: