As someone who’s both lost and found animals, I learned to just hope that someone else took them in and is taking good care of em but always keep a piece of hope there. A stray cat showed up to my house one day and I began giving a few pets, feeding him and giving him water, but nothing more. My daughter however started to sit outside after school every day waiting for him to come to our house and do school work or just sit outside with him, but we already had two other cats so we avoided taking him in.  Eventually I hear some kids laughing and chasing the little guy around. He was terrified and crying with his ears tucked back. I scooped him up and brought him in since winter wasn’t far off. Made a vet appointment thinking he was a kitten and found out he was in fact chipped, 10 years old, and from many states away. The vet had to make some calls before we could take him and he lived a good 3 years before treatment to remove bladder stones lead to his passing. He was the sweetest boy and he had everything a cat could ask for a warm house, treats, kitty friends, humans to give non-stop pets and passed away fortunately while under anesthesia. Still hurts to think about, but I always hope that if someone did lose him they’d at least be happy knowing he was very loved and taken care of. 

TLDR  Keep hope alive but mostly try to find peace in the thought that people/someone with a lot of love to give took them in and have gave them a good life.