It seems that in CS 2, a cheating vulnerability has been found—NVIDIA settings allow opponents to be seen through smoke

Data miner Tour has identified a vulnerability that allows opponents to be seen through smoke in CS2. This issue affects only NVIDIA graphics card owners. A video demonstrating the problem was posted on social media.

Through the smoke, players' outlines are clearly visible when filters in NVIDIA Freestyle are set correctly. The video's author refrained from providing setup instructions to minimize potential abuse by users.

To use third-party software that modifies graphics, simply enter the command -allow_third_party_software in CS 2's launch parameters. Tour suggested that Valve temporarily disable matchmaking access for players using this option.