Mortem

Hello, new here!! Someone commented about having the notification from the 20th of June, which is very close to when I started seeing it. I get the notification come up and I've run several scans, on both ESET and other Antiviruses, yet nothing is detected. I was wondering if someone could explain to me why this is, if what it's actually detecting is dangerous and if so how to remove it or stop ESET from detecting it please, thank you!!