Cut the cantaloupe in half and scoop out the seeds, discarding them. Slice each cantaloupe half into quarters and use a large spoon to scoop the fruit into a blender, discarding the skin.
Add the cucumber, shallots, basil, garlic, olive oil, vinegar, lemon juice and salt to the blender. Add a few twists of fresh ground black pepper. Puree until smooth.
Place soup in a large container with a tight lid and refrigerate overnight to allow the flavors to blend. Do not skip this step!