There is a toggle within the Main list view of Candidate activities that allows you to filter between Basic Activities and Advanced Activities for a more complex search.
Advanced Activities can be saved, just like any other list view in your database. This option is located under the "Activities and Marketing" tab within your Candidate filter section.
Once you click on "Advanced Activities" it allows you to filter by multiple activity types, and dates. For example, I want to see candidates who have had a telephone call within 1 week OR a candidate that has had an email within 1 month.
So now a candidate that has either one of those activities, within those timeframes, will appear in my list. You have the ability to add up to 5 advanced activity filters.