TIS-B targets on your ADS-B display are radar-relayed, not direct broadcasts - carrying up to 12 seconds of latency that can place traffic half a mile from where it appears.
TIS-B uplinks radar-derived traffic to ADS-B In receivers, but its position accuracy and latency differ significantly from direct ADS-B targets - and most pilots don't know the difference.
Radio Hangar explores The Two ADS-B Links, Ten Ninety ES and Nine Seventy-Eight UAT, and Why the FAA Has to Rebroadcast Traffic So the Two Halves of the Sky Can See Each Other.
TIS-B fills ADS-B traffic display gaps using FAA radar data, but latency, coverage holes, and non-transponder aircraft create blind spots every pilot must understand.