This prompt is brought to you by one of my colleagues at work; many thanks for the idea!
So, cryogenics. When I hear that word, my mind goes to a sci-fi place of people being frozen, either for a long journey, or to forestall a disease or condition, in the hopes of a cure being available in the future. A more accurate term for this might be ‘cryopreservation’, and on a small scale, this has already been demonstrated to work, with eggs and sperm, for example, but also with embryos.
So, the technology to freeze works (to a degree), and it will improve. Still another term for the most fantastical vision of the idea is ‘cryonics’, which is currently more of a hopeful vision, rather than a tangible idea, for it involves freezing someone post-death, in the hopes of resurrecting them in the future. Numerous problems exist with this, due to what freezing does to a body, and a lot of scientists believe it will never be possible to successfully revive someone from cold storage. This doesn’t stop the idea from persisting, because let’s face it, we as a species are always looking for ways to cheat death.
There are ethical questions too. Freeze someone, and let’s say they can be successfully revived, and cured of whatever ailed them, but it’s 500 years into the future. That person will wake up completely alone, in a civilisation that might well be completely alien to them, technologically, culturally and socially. There’s no telling how a person would react to that unique, and probably frightening, set of circumstances.