TIS-B is the new name for ADS-B, coupled to the ATC radar. It's
actually a fairly nice solution to the "chicken and the egg" problem.
It allows equipped aircraft to see not only other similarly equipped
aircraft, but also any other aircraft that ATC can see.

Unfortunately, deployment is so far only in very limited locations on
the east coast (and part of Alaska, of course). Here in Texas I don't
expect to see it for decades. [We basically don't even have TIS yet.]