According to the good people on Reddit who speak Russian, the soldiers used the male version of the term 'American', when they whispered to the prisoner at the end.
So this almost guarantees that whoever the captive is, it's a male.
Other clues that suggest it's Hopper - and not Billy - who survives at the end of season three is the fact that Hopper's car was spotted on the set of season four.
According to a picture that was shared on Reddit (which you can see HERE) Hopper's 1980 Chevrolet Blazer is seen on location in Georgia, the United States, clear as day.
The last time we saw Hopper (David Harbour) in Stranger Things he was left trapped inside the Upside Down, leaving many of us thinking he was for sure a goner, but thanks to Reddit we are starting to get some hope for Hopper's fate.
Even though we still have no idea what is in store for us in season four, all we can say is we better get an Eleven and Hopper reunion, or we'll strike.