Since both of these CPU are 2 cores 4 threads, you wouldn’t get much from upgrading CPUs

And to add to that, don’t forget to consult the maintenance manual that Lenovo puts on its support website

As far as I’m aware, you can change the battery, the ram and the storage. If you don’t have a 1080p display, that can be swapped as well. The wireless chipset can be changed, but note however that you need to get one that is whitelisted by the BIOS of the computer. The CPU is soldered to the logic board, so what you have is what you get.