In 10-inch skillet, break beef and sausage into large pieces. Cook over medium heat about 10 minutes, stirring occasionally, until browned.
Spray 4- to 5-quart slow cooker with cooking spray. In slow cooker, mix meat mixture, mushrooms, marinara sauce and tomatoes.
Cover; cook on Low heat setting 7 to 8 hours.
About 15 minutes before serving, add tortellini to slow cooker; stir gently to mix. Sprinkle with cheese. Cover; cook about 15 minutes longer or until tortellini are tender.