I'm going to upgrade.
Depends on what Your resolution and frame rate goals are and what type of titles.
Going to need a lot more information..
What is your budget.. 500? 700? 1000? 1200? etc
What type of games.. FPS? MMO's? etc
Do you want Atx, mAtx, or itx size MB/case?
What CPU AMD or Intel? GPU?
Also are you in the USA or another country? Some pieces of Pc parts is harder to get in other countries.
Once you have a rough idea on those then people can help/suggest equipment and narrow down what you might need.
I have a random budget.
Any game I want to try
Core i5 9600k (is it better than the Ryzen 5 2600X?)
Do I need a 1060? Or a 1070?
Both are really great CPU's..but for JUST gaming then the i5 9600k I would leanon BUT odds are it might be more $$ than the R5 2600k plus the i5 9600k does not come with a cooler which you will need to buy also which will cost more $ (depends on what cooler you want to put on it) where the R5 2600k comes with one.
1060/1070 should be fine for 1080p games BUT if you want fast FPS or do 1440 (2k) resolution then you will need a better GPU which then a 2060 should really set you up for a while. If you want to do 4k balls to walls stuff then a 2080/2080ti/Radeon VII is what you would need. Also with AMD Navi around the corner one of those you can use for gaming and be set for a while also :)
When I build systems for people, I always tellthem do not think on what you want the system to do now..think of what you WANT it to do in lets say, 5 years. If you are doing 1080p now lets say you want to go to 2k monitor..well your GPU MIGHT not be able to make great/awesome use of the 2k monitor.
It is a balance on getting a GPU/GPU that will together instead of trying to choke each other out LOL.
9600k? Core what?