Heat olive oil in a 12-inch cast iron skillet over medium-high heat until shimmering, approximately 90 seconds. Add diced onion and sauté for 3 minutes until softened and translucent, stirring occasionally. This develops deep flavor notes before the meat enters the pan.

Add minced garlic and cook for 30 seconds until fragrant, then increase heat to high and add ground beef. Break the beef into small crumbles with a wooden spoon, stirring constantly for 6-7 minutes until the internal temperature reaches 160°F on an instant-read thermometer. Drain excess fat if needed, leaving approximately 2 tablespoons in the pan.

Sprinkle taco seasoning over the cooked beef and stir well to coat every piece evenly. Pour in beef broth and diced tomatoes with their juices, then add red bell pepper slices and corn. Stir to combine all components thoroughly, ensuring the beautiful ground beef taco skillet has even distribution of vegetables.

Reduce heat to medium and simmer uncovered for 8-10 minutes until the sauce reduces by approximately one-third and vegetables become tender-crisp. Stir the skillet occasionally to prevent sticking and to maintain consistent cooking. Add drained black beans during the final minute of simmering to heat through.

Remove from heat and scatter shredded cheddar cheese evenly across the surface of the beef mixture. Cover with a lid or foil for 2 minutes until cheese melts completely, creating a gorgeous golden layer. Garnish with fresh cilantro and serve with lime wedges for brightness and acid balance.