Heat oven to 350°F Warm 1 tablespoon oil in ovenproof skillet over medium heat. Add shallots; cook 1 to 3 minutes or until.
lightly browned. Drain on paper towels; reserve.
Season tenderloin with salt and pepper. Heat remaining 3 tablespoons oil in ovenproof skillet over medium-high heat. Add.
tenderloin and cook until browned, about 9 minutes, turning as needed to brown evenly.
Transfer skillet to oven. Cook until internal temperature of pork reaches 155°F, about 30-40 minutes. Transfer tenderloin to cutting board and tent with aluminum foil to keep warm. Return skillet to stove top.
Add broth, vinegar, and cherries to skillet on medium-high heat, scraping up browned bits with rubber spatula. Mash cherries with fork and cook 5 to 6 minutes or until liquid is reduced to about 1/2 cup. Lower heat to medium, add butter and brown sugar, and swirl pan until well incorporated.
To serve, slice warm tenderloin on diagonal, top with sauce, and sprinkle on reserved shallots.