Ever since losing to Goku on Planet Namek, Dragon Ball’s ultimate villain, Frieza, has been obsessed with getting revenge on the Saiyan warrior. This was made clear when the Evil Emperor invaded Planet Earth in his new Mecha Frieza form immediately following his crushing defeat, and then once more in the film Dragon Ball Z: Resurrection ‘F’. However, as it currently stands in Dragon Ball canon, Frieza has already gotten his ultimate revenge against Goku – and fans totally missed it.
https://screenrant.com/dragon-ball-fans-missed-frieza-revenge-against-goku/