We have an indoor/outdoor cat, but she’s harness trained. She knows if she wants to go out, she has to stand still to have the harness and leash attached. We tether her to a stake in the yard, or to a door handle, but only when we can be watching her. We have coyotes, hawks, and owls in the area, even though we live in a suburban neighborhood. Even had a family of owls earlier this spring in one of our trees in the back yard. Her front paws are declawed, which was done after we realized nothing was stopping her from ripping up furniture, and the frame on our patio door has lots of deep scratches.
One of mine can escape from a harness in about five seconds. It's pretty amazing to watch.