The NBA’s new in-season tournament, now branded the NBA Cup , did not exist in 2020, so there was no “NBA Cup 20” winner.

What existed in 2020

  • In 2020, the league only had the traditional regular season, playoffs, and the NBA Finals played in the Orlando “bubble” due to the pandemic.
  • The Los Angeles Lakers won the 2020 NBA championship (NBA Finals), defeating the Miami Heat 4–2, with LeBron James as Finals MVP.

When the NBA Cup actually started

  • The in-season tournament that is now called the NBA Cup was first held in the 2023–24 season.
  • The Los Angeles Lakers won the inaugural NBA Cup in 2023; later editions have since followed annually.

Why there’s confusion online

  • Many forum and social posts casually say “NBA Cup” or “Cup” when talking about modern tournaments, which can make it sound like the event existed earlier than 2023.
  • If someone mentions a “Cup” win for 2020, they are almost certainly either joking, mislabeling the 2020 championship, or speaking hypothetically about if the Cup had existed then.

TL;DR:
There was no NBA Cup in 2020 ; only the regular playoffs and Finals, which the Lakers won.

Information gathered from public forums or data available on the internet and portrayed here.