Although we don’t know the facts, this behavior may well be due to jealousy.
Cats and dogs tend to get along, especially when they both grow up together.
Here you can see some examples of dogs and cats doing very well.

They are not always best friends, but they learn to coexist.
It is rare to see cats and dogs in the same house that are not good friends.
Both seek the same, to be liked by their owners.
But never forget that each one is unique and different.

Both will make you happy, but each in their own way.