When indoor-only cats escapes, they generally hide in silence. They will not meow, even if they know your voice, and they won’t call for help if they’re injured.
When outdoor cats disappear, it generally means that something has happened to disrupt their usual journey home. They may have been chased from their territory by another cat or a roaming dog. They may have been picked up by someone who thinks your cat is lost. Or, they may have got themselves trapped or injured.
Start looking for your cat as soon as you realise he/she is missing. The longer you wait, the harder it can be to find them. Don’t wait for your cat to come back on its own or find its own way back using their ‘homing instinct’. Not all cats have that ability, they can easily become disorientated, can get scared or injured.