Is he/she neutered/spayed? (If so, please ignore this question and continue reading my reply)
If you can keep him/her in- do it. If he/she keeps meowing or attempting to escape, you can train him/her to walk on a leash with a harness. This takes a few weeks of wearing the harness while inside for short periods of time, and then introducing the leash. You can use treats to reward him/her for wearing the harness and to make them associate the harness with good things like yummy treats.
There are several articles on this site that can give you more specific info on how to train your cat to walk on a harness and leash.
You can get a cheap cat harness at most pet stores, but for a better fit (and a harness that is much more difficult to escape) you can look on Etsy for custom ones. I recommend the seller: Butterfly Cat jackets. The seller Hyendry also makes very nice cat harnesses.
Also, I always recommend that any cat who walks on a leash outside also wears a collar with ID tags on it, the cat should be microchipped with your info programmed into it, so if the cat slips out of the harness, it is more likely to be found and given back to you.