Just Cause 4 is apparently existing and is gearing up for a pre-purchase phase. Well, that is what we gather from the accidental leak by Steam.

Just Cause 4 leaked on Steam

​​So, 2 things are confirmed by this leak. A.) Just Cause 4 exists and B.) it is coming to Steam. This was not the first rodeo with the leaks for Just Cause 4 as Walmart accidentally leaked a lot of unannounced games including Just Cause 4, Borderlands 3 and Rage 2.

Wario64's tweet

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The Steam blunder was spotted by Kotaku and was subsequently twitted by Wario64. Kotaku went on to click the advertisement just to be sent to Steam's home page with no indication of any store listing just yet. The ad itself is already taken down by Steam as it does not pop up when I logged in.

This is a pretty common trend as E3 is just around the corner. We can wait and see for the official announcement during the biggest gaming convention.

Source: PC Gamer, Kotaku