So this issue has happened a couple of days ago too. First attempt to start PUBG would fail with no error given. Second attempt would eventually launch the game.
Today however the game won't start at all and naturally I was blaming the game but seems that is not the case. Apparently Advanced Threat Defense (ATD) interferes with PUBG anticheat maybe? It's ATD at fault that's for sure. Once adding "TslGame_BE.exe" and "TslGame_EAC.exe" to the exception list in ATD the game starts without issues.
Neither PUBG gives an error to figure out what's going on, nor Bitdefender actually says that is blocking the program (might not even block it but just interfering with it in some way).
Multiple users reported on PUBG forums that adding those to programs to the exception list in ATD fixes the issue.
Link to post on PUBG forums: https://forums.pubg.com/topic/340990-game-doesnt-launch-no-errors-given/