Heat the olive oil in a large pot over medium heat. Add the beef and cook until browned on all sides, about 5 minutes.
Add the onion, garlic, and red bell pepper. Cook for 3 minutes until the vegetables start to soften.
Stir in the lentils, beef broth, diced tomatoes, cumin, chili powder, salt, and black pepper. Bring the mixture to a boil.
Reduce heat to low, cover the pot, and simmer for 35 minutes until the lentils are tender and the beef is cooked through.
Stir in the corn and cook uncovered for 5 more minutes to heat it through.
Remove from heat and sprinkle with chopped cilantro before serving.