WARNING: The following contains spoilers for Star Wars: The Mandalorian Season 2, Episode 8, "Chapter 16: The Rescue," streaming now on Disney+.
Undeniably the aesthetics and rich cinematography of The Mandalorian is a significant factor in what makes the show great. The character-driven stories along with the growth of the Star Wars Universe and mythology is perfectly complemented by these jaw-dropping aesthetics. In relation to that, the concept art for the series deserves recognition as not just great concept work, but stellar works of art themselves. Included in the concept art for Planet Corvus when Din Djarin encounters the Magistrate and Ahsoka Tano may actual be fan-favorite droid R2-D2.
Released concept art for Din's arrival on Planet Corvus as he stands at the gates of the city ruled by the Magistrate shows an R2 droid unit to the left of the photo. The droid appears to be watching over the scene. Given the arrival of the beloved R2-D2 in the Season 2 finale, perhaps the droid in this concept art is a sneak peak of what is to come later in the series. Though, perhaps there is more to it than simple foreshadowing. Perhaps the concept art implies something bigger than an Easter Egg.
What if Luke sent R2-D2 to Planet Corvus with a mission. In the Season 2 finale, Luke Skywalker appears to save Din and his allies while on their mission to save Grogu. Luke arrives to the Imperial cruiser because he hears Grogu's call through the force. Luke's attempt to train a new generation of Jedi is still fresh at this point in the timeline, and he is not yet jaded in that endeavor. He could be actively building a new Jedi Council of some description. In that case, R2-D2's appearance on Planet Corvus may be in a research and observe capacity while assisting Luke on his mission. Not only is the Magistrate on Corvus, but so is former Jedi, and Anakin Skywalker's former apprentice, Ahsoka Tano. Maybe R2-D2 is there for the same reason Din and Grogu are there: to find Ahsoka and learn her connection to the Jedi.
R2-D2, however, is not aesthetically a one of a kind droid. While he certainly has his own personality, there are other R2 droids in the Star Wars Universe. Therefore the blue and white droid seen in the concept art may not actually be the one fans know and love. It could be a different R2 unit all together. This inclusion of a blue and white R2 unit may just be artistic flair to add a pop of color to the edge of the frame. It also could just be a little bit of fun that has no real story significance at all.
There was no appearance of beloved R2-D2 actually on Planet Corvus; his series debut came alongside Luke Skywalker instead. It is unconfirmed if his appearance in the concept art is meant to have story significance. In all likelihood, the inclusion of a blue and white R2 droid is nothing more than artistic flair or a fun Easter Egg. Despite that, the inclusion of said Easter Egg is just one of the many interesting aspects of The Mandalorian concept art.