What Types of Features Are Most Suspect in the Medical Use Case?

The use of a detection in one like i think one experience a lot of people have had is, if you don't let your credit card company know you're traveling, they might flag your card in another city. So that feature is no longer useful in the medical use case. It's not super obvious to me how a feature goes bad. I mean, if i have a answer today, i have cancer tomorrow, unless it's cured or whatever. And would you mind sharing a few examples of what types of features are most susceptible in medical cases?