This bill establishes new background check requirements for firearm transfers between private parties (i.e., unlicensed individuals). The U.S. House passed this bill to strengthen the background check system, with bipartisan support. The bill is supported by the major gun safety groups, including Brady Campaign for Gun Safety. This bill is important to support because approximately 1 in 5 guns are sold without a background check. The background check system for gun sales has not been updated since it was first implemented in 1994. A lot has changed in that time, including most notably, the internet and internet gun sales.
 

More details here:  https://www.congress.gov/bill/117th-congress/senate-bill/529