https://www.pcgamer.com/learn-about-life-on-a-train-in-a-new-metro-exodus-overview-video/

Metro Exodus is a couple of weeks away, and if you're just now tuning in, this new six-minute video released today by Deep Silver and 4A Games will get you caught up on what it's all about. The trailer provides a nice overview of everything that's in store, from the reason you're living underground to a closer look at the world on the surface, weapon mods, crafting, and the focus on narrative over "pointless fetch quests." 

Metro 2033 and Last Light are very linear, while Exodus will be more open—not fully open world, but a series of linked hubs that you can explore as you like. (Samuel described it in more detail in his recent preview.) But like the previous games, it will still be primarily a story-driven experience.