The Boeing 757 that carries the US Vice President, and the aircraft that becomes Air Force Two. Live C-32 positions.
The C-32A is a 757-200 fitted out for senior American officials. When the Vice President is aboard it uses the callsign Air Force Two; it also carries the Secretary of State, the First Lady and visiting cabinet members, which makes its movements a reasonable proxy for American diplomatic activity.
A separate pair of C-32Bs exist and are a different proposition entirely: unmarked, operated in support of the State Department's crisis response, and turning up quietly in places that are in the news. Serial 00-9001 is one of them.
The designator B752 covers any 757-200, so civil freighters appear here too. On a military feed the government aircraft dominate.
It becomes Air Force Two when the Vice President is on board. Air Force Two is a callsign, not an aircraft, and the C-32A is the type that usually carries it.
The A is the VIP transport in full government livery. The B is an unmarked pair used to support State Department emergency response teams, and their movements are not published.
ADS-B designators describe the airframe, not the role. The C-32 is a 757-200, so it reports B752 exactly as a civil one would.