What to upgrade on my pc next ?

Hello, I am just wondering if someone can help me. I am thinking to myself what I should upgrade next on my pc ? I am a gamer and really want to get into live streaming on twitch for fun.
I will post my specs here of the important parts haha:
Asus GeForce GTX 960 Strix DCII OC 4GB GDDR5 Dual-link DVI HDMI DisplayPort PCI-E Graphics Card
Intel Core i5 4690K 3.5GHz Socket 1150 6MB L3 Cache Retail Boxed Processor
Asus Z97-PRO Gamer S1150 ATX Gaming Motherboard

Errr personally i’m at the point on what do I go for ? update graphics card ? or update my CPU ?
I was thinking about getting a
Intel Core I7-7700K 4.20 GHz Socket 1151 8MB
I don’t know I have some experience with tech but would just love advice.
Thanks in advance.