Is the app compatible with your version of macOS?
Try booting into Safe Mode to see whether the app will launch. If this works, then it most likely means that you have some other third party software installed which is interfering with the normal operation of macOS.
If Safe Mode doesn't work and you have the latest version of the app (verified it is compatible with your version of macOS), then you can try deleting the app's .plist preference file located in the hidden Library folder within your home user folder "~/Library/Preferences/". The preference file will usually have the name of the developer of the app along with the app's name, other times it may only have the app's name. If you delete the .plist preference file(s) for this app, make sure to log out of the user account, then log back in before you try to launch the app again.
Without any specific details, this is the best I can suggest. When posting to the forums asking for assistance you should provide specific details such as the exact model of the Mac, version of macOS being used (both before & after the update), and the app with the issue (including its version number.....possibly even a link to the app if it is not a common popular well known app).