@Артём3 Travel restrictions related to Covid have become so common that they're no longer considered extraordinary circumstances, so it's important to either book places with flexible cancelation or choose a travel insurance policy that covers trip disruptions.
You might just have to accept the loss on this one, but if the listing has dates available further into the future, you can try requesting a date change in hopes that travel from Ukraine to Italy will re-open at some point next year. It's entirely up to the host whether they want to grant a special exception to the policy that you booked under, so it helps to come across as someone who it would be a delight to host. That's basically impossible if there's any drama about refunds.