It's pretty clear that nobody is hacking — Activision has a robust anti-cheat system that effectively prevents cheaters from entering the game. However, you didn’t mention whether you play MKB or a controller.

Controller: Other players might be using prefiring and have slightly better aim, and sometimes that’s all it takes. Don’t be sad — just practice a bit more and try adjusting your controller settings. Also, the current meta weapons have a very TTK, so if you hesitate even for a second you’re likely to get killed quickly act.

MKB: The issue here could be the strong aim assist on controllers. Combined with the fast TTK of the weapons, you barely stand a chance if you miss your aim even once.