1. 1. Prepare the Chicken and Vegetables: Place the boneless, skinless chicken breasts at the bottom of your slow cooker. Layer the thinly sliced red, green, and yellow bell peppers, and the sliced onion over the chicken.

2. 2. Add Canned Goods and Broth: Drain and rinse the black beans, then add them to the slow cooker. Pour in the undrained can of fire-roasted diced tomatoes and the undrained can of diced green chiles. Follow with the low-sodium chicken broth.

3. 3. Season the Soup: Sprinkle the fajita seasoning mix, ground cumin, smoked paprika, and optional cayenne pepper evenly over all the ingredients in the slow cooker. Give everything a gentle stir to combine the seasonings with the liquids and vegetables.

4. 4. Slow Cook to Perfection: Cover your slow cooker and cook on high for 3-4 hours, or on low for 6-8 hours. The chicken should be cooked through and easily shreddable with a fork, and the vegetables should be tender.

5. 5. Shred the Chicken: Once the cooking time is complete, carefully remove the cooked chicken breasts from the slow cooker. Place them on a cutting board and shred them using two forks. Return the shredded chicken to the slow cooker.

6. 6. Add Creaminess: Add the softened cream cheese cubes to the slow cooker. Stir well until the cream cheese is fully melted and incorporated, creating a creamy texture throughout the soup.

7. 7. Final Touches and Serve: Taste the soup and adjust seasonings if necessary. Ladle the warm soup into bowls. Garnish with fresh chopped cilantro and any desired optional toppings like shredded cheese, a dollop of sour cream or Greek yogurt, avocado slices, or crunchy tortilla strips.