The sense of smell will most likely become vestigial for humans, or no longer function!

There are many things in our bodies that have become vestigial, such as our appendix and wisdom teeth, yet many people don’t know that our sense of smell will most likely one day disappear! 

Why would this happen? Because of evolution our bodies naturally process out things they no longer need to survive. The purpose of smell was to originally to find foods that provide us with the most amount of calories.

The part of our sense of smell that is responsible for this is called the vomeronasal organ and recent studies have shown that the active sensory neurons are no longer working like other animals because we no longer have to scavenge for our food, so our sense of smell has become useless to our survival!

(Source)