The most conflict between cats and dogs tends to happen when you are dealing with adult animals.
In truth, cats and dogs that are raised together and socialize accordingly can get along perfectly well.
If you’re planning to have both cats and dogs, there are a few things you might consider:
Adopt them at the same time, as a puppy and kitten, respectively. Young animals are less likely to act aggressively towards one another.
A cat will prefer plenty of space in which it is beyond the reach of the dog. So provide lots of high spaces like cat trees or cat walks around your home.
Separate feeding spaces. In some cases, the way a dog acts around food may be distressing for a cat. Cats like to be calm and collected when eating. Some dogs get really excited.
Be aware of possession antics, especially if you have a toy or lap dog. Cats also like to cuddle or sit on you, and if there’s only one of you around, it may result in aggression over who gets to sit where.
Some dogs have very strong prey instincts (as do cats). Their predilection for chasing small things may make them unsuitable for life with a cat.
If, after focused training, your dog continues to aggressively “hunt” your cat (or vice-versa), you may need to reconsider the pairing.