What are bitcoin mining group scams?

Could you elaborate on what Bitcoin mining group scams are and how they operate? I've heard rumors about such schemes, but I'm not entirely sure what they entail. Do these scams promise unrealistic returns on investment for participating in bitcoin mining pools? Are there common tactics that these scammers use to lure in unsuspecting investors? How can investors protect themselves from falling victim to such schemes? I'm interested in learning more about these scams and understanding the risks associated with them.