Without getting so far into the details as to provide spoilers for those who haven’t read the book, the footage suggests that the movie is going to build up to a climax that is the raid on House Atreides orchestrated by Baron Harkonnen (Stellan Skarsgard). The story will follow Paul (Timothee Chalamet) and his family as they try and establish themselves on Arrakis, known for its giant sandworms and spice mining, but all the while, as discussed in the voice over of Reverend Mother Mohiam (Charlotte Rampling), there is the looming knowledge that the Harkonnens have orchestrated the Atreides move to the planet as part of a trap.
Article source: https://www.cinemablend.com/news/2554391/things-the-dune-trailer-just-taught-us-about-the-movie