There is one semi-legitimate way people interpret "download" regarding Aim Assist:
These hardware devices are now detectable by Call of Duty's security. Using them can result in account warnings or bans. warzone aim assist pc download
If you are playing on PC with a controller, aim assist is enabled by default. You do not need to download external software to use it. Instead, you can optimize your performance through in-game settings: There is one semi-legitimate way people interpret "download"