Both are traditional Italian green sauces made by blending olive oil and garlic with herbs, spices, and other ingredients.  The primary difference between the two is that pesto traditionally includes cheese and pine nuts, whereas sauce verde does not.  Also, traditional pesto is made mostly of basil, while this Italian salsa verde is spinach and parsley based. Sauce verde often contains capers, anchovies, and other items not always found in pesto. Of course, countless versions of both pesto and sauce verde exist today, so you may find some crossover.