2012 Cadillac SRX - fob problem

2012 Cadillac SRX Just put in a new battery and it now doesn’t recognize my FOB to start it.

If you are talking about the key fob battery, then make sure you did not put it upside down.
If you are talking about the car battery then, Open and close door on vehicle, while standing outside of vehicle. Hold both the lock and unlock on remote for at least 5 seconds. Door lock should cycle. if they do then try starting it.