Thor: love and Thunder's brightly coloured trailer actually revealed a melancholy Avengers: Infinity war detail. Thor: love and Thunder sees the character return to a prominent position in his own film after a particularly trying period in his life, and embark on a voyage of self-discovery. The tragedy of losing family, friends, and his home planet appears to have taken its toll on him, and one aspect in the video bears homage to a very devastating scene from Avengers: Infinity War.
Thor lost not just his best buddy Heimdall, but also his brother Loki in Infinity War. The two had a turbulent relationship from the start, with Loki serving as the villain in both Thor and The Avengers, but after the destruction of Asgard, they came to their own form of reconciliation in Thor: Ragnarok. Their tumultuous relationship could be portrayed for laughs, as in the funny "seek assistance" scene, but it could also be heartbreaking, and by the end, there was no doubt that the two brothers loved each other.
A sequence in the Thor: love and Thunder teaser shows Thor gazing out towards the sunset, drenched in golden sunshine, which appears to be an homage to a tragic detail from Avengers: Infinity War. Loki pretends to hand over the tesseract to Thanos in order to save his brother, and as he does so, he glances at Thor and says, "I assure you brother, the sun will shine on us again." Despite their history, Loki watches out for his brother when it matters most. Loki is killed by Thanos when he tries to assault him, making him Thor's last living relative, which is why the sun only shines on him in the Thor: love and Thunder trailer.