Depends on. First of all, it depends on the airline whether you will get credit for future travel by canceling the non-refundable ticket. Note: When you use the remaining credit on the ticket, the fee the airline has given us for the "full feed" will not be fully charged. However, some airlines do not allow any credit, and if you cancel the ticket, you are out of money.
In the US, it is complicated by a rule that if you book your flight at least 2 weeks, and cancel it within 24 hours of booking the flight, you can non-ticket the ticket. - Returns of full airlines can be made regardless. To be refundable.