The Mandalorian is set many years after the conclusion of the original Star Wars trilogy, with improvements to tech like the landspeeder made famous by Luke Skywalker showing the passage of time. An emerging theme of the Disney+ show is that the benefits of the Rebels' victory in Return of the Jedi and the rise of the New Republic did not impact the galaxy uniformly, with the rough-and-tumble Outer Rim, in which The Mandalorian is set, being decidedly worse off. Advancements are still visible, however, often used either by the Imperial Remnant or by those in a lucrative but fringe line of work, such as bounty hunting.
A New Hope initially sees Luke Skywalker zipping around Tatooine in his X-34 landspeeder, which he eventually has to sell to cover his passage aboard the Millennium Falcon alongside R2-D2, C-3PO, and Obi-Wan Kenobi. As the saga progresses, this vehicle is shown to be increasingly humble in comparison to the galaxy's many grand starships, but landspeeders nevertheless recur often when the need for non-combat terrestrial travel arises.
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The Mandalorian season 2, episode 4, "Chapter 12: The Siege" shows a new, as-yet-unnamed landspeeder model that is noticeably more well-appointed than Luke's. Most prominently, it has four seats instead of two, allowing it to accommodate the full party that goes on the mission to the Imperial base. Its expanded dash also looks to offer other features, and it seems to sport an improved array of engines, although it was admittedly destroyed by Cara Dune before the crew had to test its capacity in either of those aspects.
The Mythrol owner of this speeder was very fond of it, so it might've been a higher-end model, but it had also by then been many years since the events of A New Hope and Luke's speeder was an older model even then, so some upgrades were to be expected across the board. Notably, the landspeeder seen in The Mandalorian season 1 premiere also had four seats, so that might be the standard at that point, in that region of space, especially given how different the frigid Maldo Kreis is from Tatooine.
While the Mythrol's newer model of landspeeder is a relatively inconsequential detail, it does serve to emphasize two important traits of the Star Wars universe. Firstly, the saga takes place over decades, and just as the story progresses over this time, nothing is static around it. And secondly, the series' galaxy is one of extreme economic stratification. The Mandalorian in particular is a good reminder that the grungy, "used future" aesthetic that A New Hope helped to popularize is often indicative of the relative penury with which the protagonists usually find themselves contending.