I have seen a few articles about these but not yet mentioned in here.
A new digital “health passport” is to be piloted by a small number of passengers flying from the UK to the US for the first time next week under plans for a global framework for Covid-safe air travel. The CommonPass system, backed by the World Economic Forum (WEF), is designed to create a common international standard for passengers to demonstrate they do not have coronavirus.
Plenty of arguments on both sides, of course.
The Guardian