Sony has recently applied to register a trademark for "PS5" with the Swiss Federal Institute of Intellectual Property. This may not be a huge deal in itself, but the fact that the application has now been made points to the impending arrival of a PlayStation 5 reveal event. There is some evidence this could take place in New York on February 29.
https://www.notebookcheck.net/PlayStation-5-trademark-registration-adds-fuel-to-the-fire-that-a-big-reveal-is-incoming.452181.0.html