What is not a similarity between mars and earth today?

Mars and Earth are two of the planets of the solar system. Some of the ways in which Mars is different from Earth are as follows-

The size of the earth is bigger than Mars as Earth has a radius of nearly 6400 km, whereas Mars has a radius of about 3400 km. The atmosphere of earth is primarily comprised of gases such as 78% of Nitrogen (N₂), 21% of Oxygen (O₂), 0.03% of Carbon dioxide (CO₂), and 0.9% of Argon (Ar), whereas the atmosphere of Mars is mainly comprised of 95% of CO₂, 3% of molecular N₂, and 2% of Ar. The surface gravity also marks a contrasting difference as on Mars, the gravity at the surface is only about 38%, in comparison to the gravity at the earth's surface.