Pomodoro sauce and marinara sauce are both tomato-based sauces, but pomodoro sauce is a simpler sauce made primarily with tomatoes, olive oil, garlic, and basil. It is typically simmered briefly to meld the flavors together but is not cooked for an extended period of time. Pomodoro sauce tends to have a fresh and vibrant tomato flavor with subtle hints of garlic and basil. Marinara sauce, on the other hand, is a slightly more complex sauce that is simmered longer and often includes additional ingredients such as onions, garlic, herbs (such as oregano and parsley). It also typically has a thicker consistency and more of a rich and robust tomato flavor with layers of savory and herbal notes from the added ingredients.