The Walking Dead has been coy about fan favorite Glenn Rhee's fate. But based on a little digging, Glenn, played by Steven Yeun, is alive and will be back soon, perhaps in the next episode.
The last time we saw Glenn, Nicholas shot himself in the head and pulled Glenn with him as he fell from the top of a dumpster into a swarm of ravenous walkers. Nicholas's corpse lay on top of Glenn as the walkers devoured Nicholas's intestines. The camera zoomed in on Glenn's agonized face as he cried out at the horror of the seemingly hopeless impasse.
Shortly after the episode aired, I looked up Steven Yeun's credits on IMDb, the site that profiles anyone who has appeared on film, even non-Hollywood types like me. It often lists actors' yet-to-be-released work. Yeun was credited with most of the yet-to-be-aired season six episodes and 81 total episodes of The Walking Dead--just two shy of Andrew Lincoln who plays Rick Grimes, and as many as Norman Reedus who plays Daryl Dixon. IMDb credited Yeun into 2016, the same as Lincoln and Reedus. But when I looked today, Steven Yeun's profile credits him only through the dumpster episode, and his final year is shown as 2015.
I believe that the original credits I saw were correct. It seems unlikely to me that the managers of The Walking Dead's and Steven Yeun's profiles would have credited Yeun for work in which he would not appear. Instead I believe The Walking Dead gang realized they had inadvertently tipped people off to Glenn's escape and decided to cover their tracks.