In the mess of life at the moment, a Brexit deal was struck and passed at the last minute just as 2020 faded into 2021. The rules make touring more complicated and expensive for UK musicians.
Sifting through the new visa regulations, fees and other requirements is going to be a nightmare for musicians who were used to plotting tours in Europe with free movement. Now going to likely their largest markets will be difficult when they can tour again. The Incorporated Society Of Musicians has released a handy guide to the new regulations for various countries in Europe, including what notifications must be made, whether or not visas have to be acquired, permits and more. There are also links to the various government visa websites as well. Since these could all change at some point, check back periodically.
If we can take small silver linings from the pandemic and lockdowns is that Brexit would have likely disrupted existing tours while they were happening, causing headaches like we saw with goods at Calais. Since no one can tour, this gives musicians time to understand new rules, get visas sorted (if they can ever get a gig), and maybe even lobby the government.