You have the information in your profile, so why haven't you read it once in all this time?

The first sentence of the information:
VAC bans are permanent, non-negotiable, and cannot be removed by Steam Support.

https://steamhost.cn/steamcommunity_com/discussions/forum/9/882959527688934488/

all VAC bans come from the detection of a known cheat, whether it is used on the account itself or some sort of sharing has occurred (account, library or phone number).

Users are responsible for the security of the account and all that happens on it