RQ-180

The Northrop Grumman RQ-180 is an American stealth unmanned aerial vehicle (UAV) surveillance aircraft intended for contested airspace. As of 2019, there had been no images or statements released, but growing evidence points to the existence of the RQ-180 and its use in regular front-line service. 

After the retirement of the SR-71 Blackbird in 1999, the US Air Force lacked an intelligence platform capable of penetrating airspace guarded by advanced air defense systems. The RQ-180 was designed to fulfill the mission previously accomplished by the high-speed SR-71.

https://en.wikipedia.org/wiki/Northrop_Grumman_RQ-180

https://theaviationgeekclub.com/427th-reconnaissance-squadron-is-operating-the-rq-180-uas-aviation-week-says/