Yes, Mars has carbon dioxide in its atmosphere. In fact, carbon dioxide makes up about 95.3% of the Martian atmosphere. This is in stark contrast to Earth's atmosphere, which is composed of only 0.03% carbon dioxide. The high concentration of carbon dioxide in the Martian atmosphere is due to several factors, including the lack of vegetation on Mars, which would normally absorb carbon dioxide, and the low temperatures on Mars, which prevent carbon dioxide from escaping into space.