Heat olive oil in a large Dutch oven or soup pot over medium-high heat.
Add ground turkey and cook for 5 to 7 minutes, breaking it into small pieces, until browned and no longer pink.
Add diced onion and red bell pepper. Cook for 4 to 5 minutes, until the vegetables soften.
Add garlic and cook for 30 seconds, stirring constantly.
Stir in tomato paste and cook for 1 minute.
Add pumpkin purée, diced tomatoes, black beans, kidney beans, chicken broth, chili powder, cumin, smoked paprika, oregano, salt, black pepper, cinnamon, and cayenne if using.
Stir well until the pumpkin purée is fully combined with the broth.
Bring the chili to a gentle boil. Reduce the heat to low, partially cover the pot, and simmer for 25 to 30 minutes. Stir occasionally.
For an extra creamy chili, stir in softened cream cheese during the last 5 minutes of cooking. Continue stirring over low heat until the cream cheese melts completely.
Taste and adjust seasoning. Add extra broth if the chili is too thick, or simmer uncovered for 10 minutes if it is too thin.
Serve hot with Greek yogurt or sour cream and your favorite toppings.