Many thanks to Angel for the info and link!
Der Tagesspiegel has reported that Keanu and Chad Stahelski will be in Berlin on May 6, 2019 to promote John Wick 3. They will answer questions from journalists at the Hotel de Rome on Bebelplatz in Mitte, followed by a photo session.
Note: At this point it is not known if there will be a screening of the film.