Heat a skillet over medium heat and cook the ground turkey until it is no longer pink, breaking it up as it browns. Add the diced onion and minced garlic and cook for another two minutes until the onion softens.
Transfer the turkey mixture to the slow cooker. Stir in the pumpkin puree, diced tomatoes, black beans, chicken broth, chili powder, cumin, cinnamon, salt, and black pepper until everything is well combined.
Cover and cook on low for 6 hours or on high for 3 hours.
Stir in the chopped kale during the last 30 minutes of cooking so it wilts but stays bright green.
Taste and adjust salt or spices if needed before serving.