"Lick the words that bleed from his mouth
Rip the Heavens with the horns of the south" – Chertograd by Deathstars
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(NOTE)
Bans applied by the Game Developer
Call of Duty: Black Ops III
Game Bans are not VAC Bans and they are issued by the individual game. Steam Support is unable to remove your in-game bans or to provide you with further information about your ban. All the information you can receive about the ban has been provided to you in-game. This ban was placed at the time with an insider dev build of windows running Cybersecurity tools for testing.

TL:DR Activision is simply a sh!t company.