A part of NASA's "We Asked a NASA Professional" series on YouTube, the space agency has answered the following question - "Is there oxygen on Mars?"
The short answer is "yes", but it's hardly the amount that we have here on Earth and definitely not enough for a human to breathe while walking around on the surface. To put it into perspective of how little oxygen Mars' atmosphere contains, NASA says the amount of oxygen present in Mars' atmosphere is 0.13%, compared to 21% in Earth's atmosphere. What Mars' atmosphere is rich in is carbon dioxide, which can be useful.
NASA technologists have created a piece of technology called MOXIE, or the Mars Oxygen In-Situ Resource Utilization Experiment. NASA has equipped Perseverance with a MOXIE, and only a few months ago, the rover was able to successfully extract oxygen from the carbon dioxide present in the atmosphere. The amount of oxygen that was extracted was only small, but the experiment proved the concept works.