Aliens have a dual definition: the people Trump wants out of the USA and the people from outer space.
Since people from outer space are called aliens, then it matters not whether they are from Mars or somewhere else. They are aliens. Therefore, “alien”, “Martian” and “extraterrestrial” are synonymous, except not all aliens come from Mars. Some probably come from somewhere else. In that case, Martians are a specific kind of alien. All Martians must be deported. We must build a wall.