By default, the Calendar app on your iPhone or iPad won’t show events you haven’t confirmed on your calendar view. If you don’t like this behavior and would like to see all events — declined or not — in all calendar views on your iPhone or iPad, all you’ve got to do is change a setting. Here’s how!
When you choose to show declined events in the Calendar app, you won’t actually receive notifications for them. You’ll simply see them in your Calendar app. You’ll only ever receive notifications if you change your RSVP to either maybe or attending.