ALSO, go to youtube and look for "Stranger Things season 4 table read" You can see David Harbour there with the rest of the cast.

Jim Hopper isn’t died, he’s just alive. Just watch the post credits in the end of season three, teaser trailer of season four and table read of season four. Then you will see the proof that he’s alive! Just like the rest of us.

They frickin confirmed it multiple times.

I am almost 100% sure he's alive. Though, I don't know if they were referring to Hop at the end of Season 3.

They were.

Is it confirmed?

If you watch the teaser he’s alive and working for the russians

In the teaser Hopper is in Russia, and at the end of season 3 they were referring to the prisoner as “The American” and that implies that there is only one American. Since Hopper is American, this means it has to be him.

He was confirmed to be alive by the Netflix YT channel. Stay caught up.

Yes he is obviously alive