A rather good article by VOX on the current state of Covid-19 serological testing.  This all relates to communicating your covid status using different app architectures with varying degrees of privacy and risk due to post pandemic surveillance use.

So far Tom Hanks and Madonna are part of a growing group of people who are willing to share their test results.  How this affects social distancing and thus commerce, like eating in a restaurant or taking an uber is very much TBD.

Theoretically governors are basing their re-opening plans on hard numbers regarding new cases.

In theory. And relative to risk of additional virus spread.

Covid Cleared sees the American  public as consumers of health data related to the SARS-CoV2 virus on a general level posted by Public Health authorities based on rtPCR testing, but also individual interactions related to immunity testing. We are not yet at the stage of an immunity certificate until needed research is concluded. However we can build the architecture and apps to make it possible and should do so.

Developers can access a FHIR server via an API. End users can (eventually and even now) get tested and get that data into their medical record. Depending on the level of anonymity required, that data can be shared. In some instances a Decentralized Identity can be used and for further privacy only a Zero Knowledge attribute exchanged.

This does not rely on a centralized bio surveillance or constant (battery draining) Bluetooth connection to be present, or GPS surveillance.