Can I cancel a listing?

A listing can be cancelled from the item's own page, and cancelling returns the NFT from the auction contract to your wallet. Like everything else, it is a transaction, so it costs a network fee.

Cancelling is not always available once an auction has bids on it — the button on the item's page is the accurate answer for that item, since it reflects what the contract will actually allow. If it is not offered, the auction has to run its course.