Magic: The Gathering
In 1991, Dr. Richard Garfield, a doctoral candidate in combinatorial mathematics approached an early Wizards Of the Coast to produce a board game. The CEO at the time, Peter Adkison determined they didn't have the resources to produce a board game so asked Garfield to instead produce a card game. So, Garfield went back to the drawing board and in 1993 Magic: The Gathering debuted. It was an instant success!
In 1996, the game was popular enough that the Magic Pro Tour came about. This was an invite-only tournament structure that offered over $1 million in prizes a year. To qualify for an invite, players competed in a worldwide system of qualifier tournaments and large events that to earn a spot.
In 2002, the game officially hit the mainstream digital market with Magic Online (there were a few prior video games that popped up prior to this that weren't as popular).
MTG Arena is the next current digital title they are working on that is currently in Open Beta. This digital release is designed to be more streamlined and easier to use for everyone, yet still is very playable to more advanced players. This year (2019) they plan to start holding official tournaments through Arena with official prize pools.
Today an estimation of over 12 million people worldwide play the game in person and online.