Sending people to Mars, keeping them alive there, and bringing them back (optional) is hard.
Sending robots to Mars is easier. It's been done in 1997 and artificial intelligence and robotics have made major strides since.
A semi-autonomous* settlement with life support should be built before we send people there. This will save a lot of time and make the mission far more likely to succeed than if we treat it like a camping trip and make astronauts set their own "tents" up.
* with high-level operations being managed remotely, but real-time operations requiring automation due to the unavoidably high ping between Earth and Mars