Please, indicate your current specifications (memory, motherboard, GPU, PSU ...) so that we can help you better.
It would also be important to know what you are going to use the PC for and your budget for the change.
I explain:
You have an Intel Sixth Generation processor with a motherboard (chipset ¿Z170, H170, H110, B150 ...?) LGA 1151. Its memory is DDR4 (speed 2133?)
The possibilities you have are:
A better Intel of Sixth or Seventh Generation with what you could use your current Motherboard (in the case of Seventh Generation surely should update the BIOS of your Motherboard)
An Intel Processor of the Eighth Generation. You should also change your motherboard because this generation uses the LGA 1151 version 2 that is not backwards compatible.
A Ryzen AMD processor. As in the previous case you should also change your motherboard. A possible drawback is that the Ryzen work better with high-speed DDR4 3000 or 3200, so perhaps your memory, although compatible, may not be the best.
It is important to compare prices before making a decision. An I3-8100 (4 cores 8 gen.) Is almost identical to an i5-7500 (4 cores 7 gen.) But the first costs about $ 100 less, so perhaps it is cheaper to change the motherboard.
Remember that if your windows 10 license is OEM, you will not be able to use it if you change your motherboard. If you come from the free windows 10 update you can use it using the procedure explained on the microsoft website.