When you cancel your booking, the refund rules in this case are applied according to the host's refund policy. And the refund policy can vary from one host to another and is listed in the description of the property you have chosen.
Depending on the host's cancellation policy, you may therefore be refunded in full or in part.
However, whatever the level or amount of the refund, it is instantaneous when the payment of your booking has been made by PayPal. But it will take 5 working days for the refund to appear, if you have paid for your booking by credit card (Visa, MasterCard, Discover, American Express, etc.).