There won't be any more evolving as far as humans are concerned.
Evolution requires natural selection through selective pressures.
Very few of those still exist. Medical science and engineering have seen to that. With time, instead of growing immunity or naturally eradicating genes that are suceptible to ailments or situations, medicine and engineering will continue to breach the gap until it's closed completely. From an evolutionary standpoint anyway.
The next steps for humans are transhumanism and genetic selection. You select your child, with exactly the features you want, from a pool of billions of fertilised eggs and then upgrade it with a plethora of chips, circuits, plugins and peripherals.
"I'll never do that. It's evil."
Cool, but your neighbour will. Which means your kid will forever be at a disadvantage. It won't be about wanting to. It'll be about having to.
Follow that through to it's natural conclusion of an unlimited IQ society fitted with as many extra senses as is affordable and as much processing power as Intel can supply, then you realise that the human future is nothing at all like the human present.
A 500iq person, fitted with hard drives and processing chips that allow for photographic memory and computer like calculation accuracy is already an intimidating prospect. When you add the ability to hear all sound frequency and to see and receive all other spectrums...then you start to see the picture of what is currently partly possible and will be entirely possible in the near future. What that generation comes up with and where they steer humanity is anyone's guess. The only certainty is that we'll have much more in common with rats than we will with what humans will be.
Evolutionary principles may only be valid as relates to bio-mimicry and simulation. Natural selection in it's pure form, as far as humans go...totally irrelevant.
Sounds like doom and gloom?
Not to me. Don't get me wrong, I don't like the idea of natural humans becoming extinct at all. The idea of cyborgs is as frightening to me as it is to everybody else.
It's when one looks the bigger picture, the much bigger picture, that things become vastly more acceptable.
Earth won't/can't sustain life forever. There is a deadline. The sun will kill us and everything else here. A long time from now, but that's the hard deadline. Between now and then, there will be many soft deadlines, each of which need to be overcome if we want our species to survive. Our habitat is, as far as we know, the exception to the rule in terms of what our galaxy and the universe at large is comprised of. We live in the 0.00000000000000000000......1%. Anywhere else would kill us.
Present humananity struggles to overcome challenges posed within our habitable environment, and that doesn't bode well for our chances against the universe at large.
While a transhuman future is not a pretty prospect, the innovation and advancement that it will bring may be our only hope at sustaining the species in the long term. Which is, I guess, the goal.