Hey there,
Well, it depends on a number of things for me.
What is your main usage?
What resolution monitor do you have?
What exactly do you want to achieve?
What PSU do you have?
Your CPU is still very capable, and overall for 1080p gaming is pretty solid. There are some CPU heavy games like BFV that might push your CPU a bit. But still decent enough.
I'd prob go with a base upgrade like this:
PCPartPicker Part List
CPU: AMD Ryzen 5 3600 3.6 GHz 6-Core Processor ($194.79 @ OutletPC)
Motherboard: MSI B450M PRO-VDH MAX Micro ATX AM4 Motherboard ($79.99 @ Amazon)
Memory: Corsair Vengeance LPX 16 GB (2 x 8 GB) DDR4-3200 Memory ($82.98 @ Amazon)
Power Supply: SeaSonic FOCUS Plus Gold 650 W 80+ Gold Certified Fully Modular ATX Power Supply ($99.99 @ Amazon)
Total: $457.75
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2019-09-15 10:38 EDT-0400
With your existing hardware, (not knowing PSU, so I've included a good one!) you would have a solid base system with an upgrade path, and a CPU that could easily drive your new GTX2070/2080.