Previous car models (and all other brands right now) use a radar signal to measure the distance and relative speed to obstacles and other cars in front of your car. Tesla has now decided to migrate to a camera-based system that uses artificial intelligence to calculate that distance and speed, much in the same way we humans do it. They call it Tesla vision.
I have been wondering how it compares to a radar system, in particular in low-visibility situations (rain, snow, smoke, etc). It must be "good enough" that they decided to switch, and it will potentially continue to improve as the technologies involved improve. There is no choice, though, for end users. All Model 3 cars now come with Tesla vision.