Okay kiddo, have you ever hear the term "race"? It refers to different kinds of people who look different, like some people have white skin, some have brown skin, some have black skin, and so on.
So when we talk about "race of the future" we're wondering what kinds of people there will be in the future. Well, the thing is, nobody really knows for sure! But we can think about a few things.
First of all, people are always changing. So in the future, there might be new kinds of people that don't exist yet. Maybe people will be taller or shorter, or have bigger eyes or smaller feet. We don't really know!
Also, people are always moving around and mixing with different kinds of people. So in the future, there might be more people who have mixed backgrounds. Maybe someone's mom is from China and their dad is from Mexico, for example. When people have parents from different cultural backgrounds, we call them "biracial" or "multiracial."
Finally, it's worth noting that the idea of "race" itself is something that people made up a long time ago. Nowadays, scientists believe that there's really only one "race" of human beings, and that we're all just part of that one big group. So in one sense, the "race of the future" might just be... humanity!