When you open a Campaign Report (by clicking on a campaign name), you will get the default view of a Campaign Report:
In the top right corner, you can see an option mentioning the said Default View!
If you click on it and you don't have a saved view, you will only be able to save the current one:
Once you give a name to your view you'll be able to re-use it and select it in all your campaigns.
If you want to update your current saved and selected view you can use the button below.
You'll also notice that there is an option to get some Custom tabs - here's what you see when you click it:
In there, you can add some Widgets for a specific campaign (or several, depending on whether you did a grouped report or not).
These widgets will be limited to these campaigns, and they can also be saved when you save the view!