-Under Construction- Cyborgs are part biological and part machine, making them fully badass on both sides. Some of the coolest fictional characters of all time have been cyborgs; but cyborg technology is already real, and improving constantly...
The basic idea of a person with non-biological parts is actually quite ancient.
In the Greek myth of Tantalus, he cooked his son Pelops and served him to the Gods and Goddesses. Only Demeter took a bite of the mystery meat before they all realized it was from human. At that point, the Gods and Goddesses put all the remaining pieces of Pelops back together and brought him back to life, and had an ivory shoulder crafted to replace what had been eaten. This may have been history's first example of any kind of cyborg.
We might argue that ivory is actually an organic material; but that doesn't really change the basic idea of prosthetics.
Once science itself began to move forward, the imaginations of many writers began to turn toward exploring the interesting new possibilities this created.
The Man Who Was Used Up
Steve Austin (the 6 Million Dollar Man...not Stone Cold...)
What does this mean for humanity?
It's probably a pretty significant thing for people to be able to technologically adapt themselves. There's really no way that this won't be a fairly major change for humanity overall.