This is what we found on Wikipedia regarding the NAB Cup:

The Arena Football League (AFL) was a professional arena football league in the United States. It was founded in 1986, but played its first official games in the 1987 season, making it the third longest-running professional football league in North America after the Canadian Football League (CFL) and the National Football League (NFL) until the AFL closed in 2019.

The AFL played a formerly proprietary code known as arena football, a form of indoor American football played on a 66-by-28 yard field (about a quarter of the surface area of an NFL field), with rules encouraging offensive performance, resulting in a typically faster-paced and higher-scoring game compared to NFL games. The sport was invented in the early 1980s and patented by Jim Foster, a former executive of the United States Football League (USFL) and the NFL. Each of the league's 32 seasons culminated in the ArenaBowl, with the winner being crowned the league's champion for that season.

From 2000 to 2009, the AFL had its own developmental league, the af2. The AFL played 22 seasons from 1987 to 2008; internal issues caused the league to cancel its 2009 season, though the af2 did play. Later that year both the AFL and af2 were dissolved and reorganized as a new corporation comprising teams from both leagues, and the AFL returned in 2010. The league's average game attendance after returning in 2010 was approximately 9,500.

The league historically had a nationwide footprint, and was recognized as the most prominent professional indoor football league in North America, offering higher payment, more widespread media exposure, and a longer history than competing leagues. From a high of 19 teams in 2007, the league contracted to a low of four teams in 2018, all in the northeastern United States. There were six teams playing in 2019, the league's final season.

On October 29, 2019, league commissioner Randall Boe confirmed reports that the league had discontinued operating teams in local markets for the 2020 season. Four weeks later on November 27, league commissioner Boe announced via Twitter that the league as a whole had filed for Chapter 7 bankruptcy, dissolving the league for the second time.