Yes, basketball will be in the 2020 Olympics (postponed to 2021).
Basketball will be included in the 2020 Olympics. First seen in the Olympics as a demonstration sport in 1904, men's basketball fully entered the Olympic program at the 1936 summer games. Women's basketball was added in 1976.
A common deviant of basketball, 3-on-3 (stylized as 3x3), will debut at the 2020 Olympics. This version of basketball is played with slightly different rules, such as taking place in the half-court and ending the game when a team reaches 21 points. This comes after the rise of the BIG3, a domestic 3-on-3 basketball league formed in the United States and global interest in the format steadily increasing.
Basketball's country of origin (the United States) has thoroughly dominated the sport internationally. The U.S. men's teams have claimed 15 out of 18 possible gold medals in the Olympics, while the U.S. women are 8 for 10.
The U.S. men's team has produced two of the greatest men's basketball teams of all-time for the Olympics: the 1992 "Dream Team" and the 2008 "Redeem Team". The Dream Team was assembled for the first Olympics that allowed NBA players to compete, while the Redeem Team came in the wake of a disappointing bronze medal finish in 2004. Both dominated their competitions to win gold medals.