Is there life on Mars?

In ancient times, life did exist on Mars. About 3 billion years ago, the climate of Mars was relatively suitable, the atmosphere had not disappeared, life could still exist on Mars, and there was a lot of liquid water, but life on Mars soon came to an end. According to human exploration of Mars, it is known that there are vast plains and towering extinct volcanoes on Mars, as well as dry riverbeds left by the erosion of ancient rivers. However, the atmospheric density on Mars is only 10% of that on Earth, of which 95.3% is carbon gas, 2.7% is nitrogen, 1.6% is argon, and there is a small amount of oxygen, carbon oxides and water vapor, which is not suitable for human habitation.