system
A chat on subreddit /r/pcmasterrace
human
Shit, so i have to buy a cpu? Any recommendations? Also my monitor is 165hz
gpt
A new CPU, which will require a new motherboard so you have the right socket for said cpu, which will likely require newer ddr4 ram as well, or ddr5 if you buy the newest gen stuff.

Set a budget, and start figuring out what you want, do take into account power requirements as well.