Hiddlestoners, it's time to face the facts: Loki doesn't have the best karma. As great as it's been having Tom Hiddleston in the Marvel Cinematic Universe as their best villain, the question will Loki die in Avengers: Infinity War pretty much answers itself when one looks back at Loki's journey in the MCU. Nothing is certain yet, but there is some pretty strong evidence that Loki will die in Infinity War.
Loki is not in a great place when Infinity War begins. The last time we saw him, at the end of Thor: Ragnarok, he was on a ship with his brother, Thor, heading to Earth when Thanos caught up with them. Based on trailers for Infinity War, a battle ensued, throwing both the Hulk and Thor from the ship. (Shots in trailers show what appears to be Bruce Banner crashing into Doctor Strange's New York Sanctum and Thor colliding with the ship of the Guardians.) It's unclear what happens to Loki in this exchange, but whatever it is, it cannot be good, and here's why: Loki has a history with Thanos.
In Avengers, it was Thanos who gave Loki the Mind Stone to power his staff (the Infinity Stone currently lodged inside Vision's head), promising him Earth in exchange for the tesseract. Loki, as we all know, failed in his evil plans, but escaped Thanos' wrath while in Thor's custody. In other words, by the time Thanos and Loki meet in Infinity War, Loki has managed to lose two Infinity Stones, something that cannot endear him much to the big bad.
That said there is hope for Loki in the form of the Tesseract. Though not explicitly stated in Thor: Ragnarok, it is heavily implied that during the final battle against Hela, Loki picked up the Tesseract from the Asgard vault. Trailers for Infinity War appear to show Loki handing over the Infinity Stone to Thanos, perhaps as a gesture of goodwill. How much goodwill that gives him is the question. Trailers also show Loki clearly surrounded by Thanos' followers, being held by force (see the photo below). Thanos could very well accept the Tesseract and kill Loki anyways — he does love death, after all.
Assuming Loki does die in Infinity War, the question remains: will he die a villain or a hero? Loki has always been a lovable villain, but in The Dark World and Ragnarok, he's transitioned from a big bad into more of an unreliable ally. While it's quite possible that Loki will beg Thanos for his life by offering to join his quest for the Infinity Stones, it's equally possible that he'll die a hero, willing to sacrifice himself instead of joining Thanos. This last option would make Loki's death especially painful for fans who have loved watching his character's shifty morals, but it would also be extremely heartbreaking for Thor, and thus a great motivator for the God of Thunder in his fight against Thanos.
In exploring the theory that Loki will die in Infinity War, ScreenRant posited that the shot of Thor screaming (see below), his head being held firmly in Thanos' grip, could be a shot of Thor crunching his skull, but it's more likely that it is Thanos forcing Thor to watch as his brother is executed. Furthermore, a report from Nerdist hypothesizes that Loki's death will come early in the film. This would be a great way to establish Thanos as a super villain with actual consequences in the MCU, while also starting Thor's Infinity War journey.
Despite all the evidence that Loki will die in Infinity War, fans of the famous trickster still have reason to hope. If Loki dies in Infinity War, it wouldn't be the first time. Loki faked his own death at the end of Thor: The Dark World, and he pretty much stayed "dead" through Avengers: Age of Ultron, only to return in Thor: Ragnarok. Cheating death twice might be a bit repetitive, but where Loki is concerned, no option can be left out.