Some dogs and cats are fine together introduced at later times in their lives, others are not. We have had multiple adopted dogs, dogs from breeders and foster dogs, as well as cats. We introduced Alaska, Georgia and Kenai to our Maine Coone cat, Jenna, when they were puppies. They were scared of her at first, and that actually helped the relationship between cat and puppy; they grew and as the dog got bigger than the cat, they formed a relationship not just revolving around puppy-terrified-of-kitty. Now, we have also introduced adopted dogs of older ages to cats in the home, and you need to be careful when doing so. A leash is the best option, maybe a spray bottle if the cat decides to be the aggresive one. Sometimes they just click, sometimes they aren't even interested in eachother, sometimes all hell breaks loose, it really depends on the dog and the cat. Sometimes even when they do start out with tension, or more, it is possible to train or rehabilitate it out of the dog so they can at least live in harmony.
Samwise (Border Collie x Labrador) was introduced to the cat at 5 months old, I believe, and he was just terrified of her and pissed everywhere when he saw her. Buddy (brindle APBT) was introduced to the cat at 2 years old, and he woofed a little, and then left her alone, but he still chased her every once and a while; never harmed her. Curve (black and white APBT) was introduced to the cat at 2 years old, they seemed fine at first; a little tension... and when we accidently left the laundry room door open where the cat sleeps, Curve went in there and attacked her. We couldn't get Curve's jaws off Jenna, but finally we did, and Jenna ended up urinating all over herself, and getting a broken leg, and hiding for days. We attempted to train Curve and Jenna to live in harmony, but it just wasn't happening, but since Curve was a foster dog, she found a forever home soon anyway, and Jenna soon healed, with a little extra beef towards any dog that came into the home.
So, be cautious with any dog or cat, any breed or age. It can happen perfectly, or not.