Why he might be dead: Before Eugene bravely offers himself up as a diversion to lead the Saviors away from the group in the RV, he shares two very sad, very touching moments with Rick and Abraham, even handing over his bullet-making recipe. When he shows up as a prisoner in the Saviors' ambush a few minutes later, however, it's a total red flag that 1.) Eugene is literally the most useless character on the show, and 2.) he could be the one to die.
Why he might not be dead: Despite all his bravery in the final episode, Eugene is a pansy, and seeing him helplessly go down at Negan's hand would be super rough. Almost icky, even.