It is a new material that has been synthesized by South Korean physicists that, according to them, is superconductive at room temperature and atmospheric pressure.

This would be a collosal scientific breakthrough if it can be replicated and confirmed. Other superconding materials only work at extremely cold temperatures or high pressures, making them extremely expensive and/or difficult to produce as well as impractical for widescale use.

The material itself is a lead based crystal, with some of the lead atoms replaced with copper atoms. This creates internal strain in the material that allows quantum tunneling of electrons through the material, resulting in the low resistance.

Because of some recent alleged scientific misconduct of another physicist working in this field, the scientific community has been a bit skeptical of the claims thus far. The author's originally submitted their findings to the most prestigious journals (Science/Nature) but they were not published there until they could be corroborated and replicated due to the ongoing controversy of the other physicist.

However, unlike other superconducting technologies, this material is relatively cheap and easy to produce so there are many ongoing attempts to try to replicate the results and we should get clarity soon either way whether this is truly a society changing technology, or another "too good to be true" headline.