Add cream cheese and mayonnaise to a food processor and blend until smooth.

Add the green olives, garlic, and black pepper, pulsing until the olives are evenly mixed but still slightly textured.

Add 1 teaspoon of olive brine and blend. Continue adding brine, a little at a time, until you reach your desired consistency.

Transfer the dip to a bowl, cover, and chill for at least 2 hours before serving.