Place the ground beef in a large bowl. Add the taco seasoning, black beans, corn, breadcrumbs, egg, salsa, and half the cheddar cheese. Mix with your hands until evenly combined.
Shape the mixture into a loaf that will fit inside your slow cooker. Line the slow cooker with parchment paper or lightly grease the bottom.
Set the loaf in the slow cooker. Cover and cook on low for 6 hours.
Sprinkle the remaining cheddar cheese over the top of the loaf. Cover again and cook for 15 more minutes until the cheese melts.
Lift the loaf out using the parchment paper. Let it rest for 5 minutes before slicing.