He is depicted as a mixed breed dog, but his specific breeds are not identified.
The filmmakers intentionally avoided defining his breed to make him relatable to a wider audience and symbolize the idea of being a "mongrel" or a "mutt" with a heart of gold.
So, while we can't say for certain if he's a Schnauzer mixed with Cocker Spaniel, it's highly likely he's a blend of different breeds, reflecting the commonality of mixed-breed dogs in real life.