**WARNING: CONTAINS SPOILERS**
Stranger Things is probably one of the most popular shows on Netflix by far. Its third season was just released on July 4, and so many people (including myself) were eager to watch it all through on the day of release. Finishing all eight episodes was an emotional rollercoaster, to say the least. El lost her powers, the Byers move out of Hawkins, and two of the main characters die, or so we think.
Of course, we're all aware of the tragic death of Billy Hargrove in the last episode when the Mind Flayer basically destroys him, but we also see that Officer Jim Hopper also, apparently, dies. We, as well as the characters, are quick to assume this due to the fact that everyone disintegrated from the machine that powers the portal, so Hopper does as well since we don't see him for the rest of the episode. You can also tell by the context clues when Joyce Byers looks at El after escaping the underground lab with tears in her eyes.
However, if you pay attention during the post-credit scene of the last episode, you will notice that as the Soviet guards are walking in a bunker, they stop at a door. One of the guards says, "Not the American," and they proceed to the next door where they grab a Russian man, put him in a cage-type room and feed him to a Demogorgon (which we also thought were gone at the end of the second season, after El closed the gate).
What American could these guards be talking about? My guess here is that they are, in fact, talking about Hopper. He survived the explosion, and the Soviet survivors must have kept him as a prisoner and brought him back with them to their base in Kamchatka, Russia. Also, the Russians have always referred to him as "the American." They never referred to any of the other Americans that they've seen like this.
Why do I strongly believe this? It's simple: Stranger Things most likely wouldn't kill off one of their main and beloved characters. Hopper has been a huge part of the show since its first season, and he will most likely be a huge part of it in season 4. Not only this, but we are never shown Hopper's actual death. The show has projected other characters' tragic deaths throughout the show like Barb in season 1, Bob in season 2, and Alexei, Grigori and (most notably) Billy in season 3. Why wouldn't they show the death of this major character if they graphically showed the death of the other ones?
We won't find out whether or not this conspiracy theory is true until season 4 is released, but until then, I don't believe that Hopper is dead. The characters may believe it, and some fans who didn't pay close attention may believe it, but I certainly don't. Hopper is not dead. He is very much alive, and he will be seen in the fourth season.