LiDAR doesn't work well in rain and it's just a ray of infrared laser light scanning surroundings, so it can be obstructed the same way as cameras; radar is what you want. But NVidia uses just 3 normal cameras and deep learning to drive in rain/snow/night and it seems to be working for them.
All of them use both, and in multiple instances of each. So they might have two front LiDARs, two side LiDARs, one rear LiDAR, one front and one rear radar, ultrasonic sensors etc. and then perform a sensor fusion to map car's surroundings.
