For centuries Mars has been isolated from the rest of humanity. Earth and, by extension, the genesis of humanity, is a legend at best. No one comes to Mars, and almost no one leaves. Space travel is prohibitively expensive and only those who manage major corps, the EDs, can afford it. Mars is governed by a loose affiliation of corps who manage, and sometimes clash over, the various territories on the planet.
Efforts to terraform Mars were abandoned shortly after it’s initial colonization, as the loss of it’s magnetic field and lack of a spinning core make the effort both extremely expensive and technically challenging. To make Mars habitable domed cities, arcologies, and underground complexes were built by the corps. It’s fairly quick and easy to get around Mars as all major settlements are connected by maglev trains. There are rumors that some, on the fringes of society, have left the domes to form their own communities outside of corp control.