Preheat your grill to medium heat.
Season the ground bison with salt and black pepper.
Form the meat into a burger patty slightly larger than the bun.
Grill for approximately 6–7 minutes per side for medium doneness, or cook to your preferred temperature.
During the last minute of cooking, place the Pepper Jack cheese on the burger so it melts.
Toast the bun lightly if desired.
Spread herbed mayonnaise on the top bun.
Layer the bottom bun with butter lettuce and tomato slices.
Place the grilled burger on top, followed by the melted cheese and sliced avocado.
Close the burger with the top bun and serve immediately. This Avocado Pepper Jack Bison Burger pairs wonderfully with fries, sweet potato wedges, or a fresh salad.