Have you looked into the market for cough detection devices? Using your audio device in smart microphones stationed strategically, people coughing can be easily detected and help alerted immediately. using ml your device will be able to distinguish between the simple clearing of the throat versus an actual pulmonary based cough. For example, just like smoke alarms and carbon monoxide detectors today, you could position cough detection devices in hospitals, nursing homes, amusement parks, shopping malls, airports, etc.
Not us personally - we don’t build devices - but the community has! See f.e. @kthakore’s work on this at Hackster: https://www.hackster.io/edge-impulse/cough-detection-with-tinyml-on-arduino-417f37?auth_token=87f6ae22332a9e56a6311601138a8f12