According to the search results, the population of Mars is a topic of debate. Here are the different answers found:

• According to the Expanse Wiki, Mars has a population of four billion humans (TV: ten billion), and is governed by the Martian Congressional Republic.
• According to AZ Animals, Mars has a population of zero, as there is no known life on Mars. However, if you count robots like rovers and landers, that answer would change. NASA has sent space vehicles to study Mars and gather information.
• According to a Reddit post on r/HaloStory, Mars and Luna were the first colonies humans established outside of Earth, and they are so close to Earth that they may have the biggest populations of all the human worlds outside of Earth. The post suggests that the populations of both celestial bodies were in the hundreds of millions if not in the billions.
• According to World Anvil, Mars is home to an increasing number of colonists from Earth, surpassing the native Martian population in 2206. The current population is 1,923,000.
• According to IFLScience, if you include rovers and landers in your population count, the Red Planet is positively teeming with "life", or the pitter-patter of robot wheels at least. There are currently three rovers, one lander, and one orbiter on Mars.
• According to Wikipedia, there is no definitive answer to the population of Mars. The planet has no indigenous population, and the only humans on Mars are currently a few dozen scientists deployed on short-term missions. However, there are plans to establish a permanent human settlement on Mars in the future.

In conclusion, the population of Mars is not a straightforward answer. While there are no indigenous populations on Mars, there are different estimates of the number of humans and robots on the planet.