Add the cubed white American cheese, shredded Pepper Jack cheese, and cubed cream cheese to your slow cooker.
Pour in the can of Rotel (including all the juices) and the milk.
Sprinkle in the cumin, garlic powder, onion powder, and cayenne pepper.
Cover and cook on low for 1.5 hours, stirring every 30 minutes to ensure even melting and prevent sticking.
Once the queso is smooth and creamy, give it a final stir to combine everything beautifully.
Switch to the "warm" setting to keep the queso at the perfect dipping temperature throughout your party.
Garnish with fresh cilantro and diced jalapeños if desired, and serve with tortilla chips, soft pretzels, or fresh veggies.