Overwatch introduced workshops into the game in April 2019 as a space for players to experiment with different customizations and items.
A new trend has seen players perform musical pieces with pianos in the workshop. Another Overwatch player performed Mario songs on the piano. This included the songs from the title screen, Browser levels and Peach's castle.
Redditor u/FlareGT performed the Cantina Band song from Star Wars. The player has also had previous experience with other songs. After many fan requests, the player chose to perform this song.
Using a MIDI file converter, players can play music on custom Overwatch matches. The MIDI converter turns the MIDI file into custom Overwatch game settings. Players will need to enter the game settings provided by the converter before being able to perform.
The music is then played by players with the help of invisible Symmetras. The hero Symmetra uses the Photo Projector to shoot ranged beams to each key of the piano. This can be done with a wide variety of songs but will take work to be completed.
So far, this has been shown to be capable of by PC players. Console players do not have the same level of freedom or access to customizing their own workshop modes yet.