If you haven't met Chris Mosier yet, allow this new Nike ad introduce you to what he's all about. In the video above, Mosier, Team USA's first transgender athlete, acknowledges that he's had to deal with a lot of uncertainty to get to this point. Would the men's national team accept him? Would he be fast enough? Strong enough? As he says in the ad, he didn't know the answers to these questions — but that didn't stop him.Mosier made Team USA in time to compete in the World Duathlon Championships last June.In January of this year, the International Olympic Committee concluded that trans athletes should be allowed to compete without undergoing sex reassignment surgery.Although you won't see Mozier in Rio this year (the duathlon, Mosier's event, isn't included in the Olympics), he told CNN in February that simply joining the team was a major step forward for him — and for the trans community."I'm just happy about what this means in a broader sense for the sport in helping young athletes... What I like is that a young, skilled athlete will now have the opportunity to go to the Olympics without a problem," Mosier said.