I hope ye know that there's a lot of botnet/ransomware type shit embedded into cracks/keygens of many popular torrents that most antivirus can't pick up, simply by their nature. Most of the time it's a dropper, so that while it does its job of crackin' whatever software it's for, it also unpacks other shit in the background like botnets.
Latest example be R.G Mechanics Witcher 3 torrent, which unpacked cryptolocker into yer computer.
tl;dr: fuck public trackers