Heat olive oil in a large pot over medium heat.
Add chopped onion and bell pepper; sauté until softened.
Stir in minced garlic and cook for another minute.
Add chili powder and cumin, stirring to combine.
Incorporate diced tomatoes and pumpkin puree, mixing well.
Add black beans and season with salt and pepper.
Pour in 1 cup of water or vegetable broth for desired consistency.
Bring the mixture to a simmer.
Reduce heat and let cook for 20 minutes, stirring occasionally.
Serve hot, garnished with fresh cilantro.