I think genetic engineering is the most high-potential tech right now. They’re already using it to cure sickle cell, and my (total non-expert, probably way too hopeful) pipe dream is that we could basically treat it like we can open a terminal on the body some day and change whatever we want.

Edit: I just want to point out that I’m imagining curing cancer, reversing aging, etc. Not like, additional orifices or anything.