You may be the kind of person that often wonders why your hand has yet to grow skin around your smartphone for the sake of convenience, but there are people hard at work in labs around the world at this very moment hoping to up the ante with technology in that direction. Let's preface this all by getting something out of the way; cyborgs are no longer science fiction. Humans who are at least some part machine, in some cases more machine than man, do exist in this day and age. There are formerly blind people walking around with perfect vision thanks to artificial eyes. There are people sporting bionic limbs as advanced as the one Big Boss has in Metal Gear Solid 5 – in fact, Konami gave a disabled fan an exact, working replica of that very arm, minus the rockets and lightning and such, of course. People have implanted RFID and NFC chips into their hands for various reasons. There are even bionic hearts in development that could turn a heart attack from a death sentence to a near miss in the future. With that out of the way, it looks like the next frontier of the cyborg movement is going to be artificial skin.
Back in 2004, an "electronic tattoo" of sorts made its way out of a lab. In the intervening 12 years, that has evolved greatly. Skin overlays and setups using pico projectors that can turn an arm into a touch screen and a hand into a dial pad are in the works, among other things. Right now, scientists aren't looking into improving the functionality as much as they're looking into exactly how to take these artificial skin technologies from the outside to the inside. That is, either implanting them in your skin or, as an option for burn victims and the like, creating a tech-laden artificial skin that can go directly over muscle tissue just like the real deal, but with more "features" than actual skin. There are a decent amount of issues here, ethical ones notwithstanding.
Using artificial materials like silicon will not allow for the kind of movement that skin is capable of, and using more flexible, organic material is a bit on the dangerous side due to one element; carbon. Humans are carbon-based lifeforms. All of our organic tissue, in one way or another, involves carbon. Naturally, this means that carbon-based tech solutions would be a good fit for implants, artificial skin and the like, right? Actually, no. The carbon passes through blood cells and could thus wear away over time, absorbing into us and leaving bare circuits that won't hold up on their own, or triggering an adverse immune reaction that some believe could cause tumors. The risk of a human body rejecting the electronics once blood moves through the harder carbon layer is also very real, which could cause a huge range of problems. With the nature of electronics, being non-living and having electricity passing through them, there's no telling what the side effects of that could be at this point.
The other issue with carbon-based circuits is an issue of electronic performance. To put it bluntly, these circuits would perform nowhere near as fast, electrically, as silicon-based circuits. This means extremely slow data throughput and low electrical power. A setup that would otherwise have the speed and computing power of a Samsung Galaxy S7 would end up severely reduced. While even that would have its uses, it's not enough to justify the kind of invasive processes involved in implanting this "e-skin" into a patient. Arguably, the system would absolutely have to be infinitely upgradable, have a kill switch, be easy to remove, and be extremely powerful to begin with. With all these roadblocks, cyborg technology is going to advance in other scattered directions for now, but when there is a breakthrough, the scientific community is extremely likely to converge on the concept of e-skin.