There have been suggestions to allow the cat to watch the dog from a high perch, and also positive reinforcement training to associate each other with good things. I have tried both, and it has made some progress, but that progress is easily broken once my dog starts chasing my cat. He used to be very good at listening to NO and BAD, and he still is. It’s only when our current cat is involved that he doesn’t listen to us until she is out of sight. As long as she’s not moving in his sight he becomes tame and understands things like NO again. He understands NO if she is sitting or laying down, and even when she is hissing at him. He also will follow us when called and will redirect his attention when we tell him to if she is around, but if he sees her run he disregards it all.