"How can I report a player if I believe that they use cheats on servers protected by the VAC system?
If you think that a player uses cheats in the game, you can report it through the Steam community or in the game itself. To report via the Steam community, you need to open the player's profile.

To open a player's profile in the Steam community from the game:
Press Shift+Tab (default) to open the Steam overlay.
In the "Friends" panel on the left, click "List of Players".
Find the suspected player in one of the tabs and click on their avatar.


After opening the player's profile in the Steam community, follow these steps to report them for using cheats:
Click on the " ... " button in the upper-right corner of the page.
In the drop-down menu, select "Report".
Select "User uses cheats" > "Request verification of this account", describe what happened and specify the game in which the cheats were used, and then click "Send a complaint".


To report a cheater in Counter-Strike 2:
Hold down the Results table view key (by default, the Tab key).
Press the alternate fire / aim key (right mouse button by default) to display the mouse pointer.
Right-click on the name in the results table and select "Report".
Select the violations that you noticed in the player (cheats for viewing through walls, aiming, and/or others), and click "Accept".

To report a cheater in Dota 2:
Open the score table during the game.
Find the suspected player and click the checkbox next to the portrait of their hero.

More information about the Valve anti-cheat can be found here. Please note that if you are playing on an insecure server or community server, you need to report the use of cheats to its administrator. Steam Support cannot block players for violations on insecure or community servers."