In 2008 KAL was fined $200 million for price fixing of cargo rates along with some other airlines.
To be fair, British Airways and Virgin Atlantic were also involved if I remember correctly, amongst others. And recently, there was another price fixing case that came to light that involved quite a few more very well known international carriers, to include Qantas, BA, Singapore, AirFrance, KLM, Cathay, Emirates, Korean, and more.