In the past, the title holder (most hijacked) was the Game of Thrones series from HBO. However, because the series had ended, the new king moved to The Mandalorian. The Mandalorian itself was actually in third place in 2019, and was quite successful, encouraging many people to follow it in its second season (which is now over).
Nonetheless, the fact that the series was heavily hijacked isn't all that surprising. Similar to Game of Thrones, The Mandalorian requires a subscription to a streaming service, which in this case is Disney +. Disney + services are not yet available worldwide. so this is also one of the factors causing piracy.
Even so, piracy will not necessarily decrease if Disney + services are available worldwide. There are still many who are looking for "creative" ways to watch the series without having to pay. The Mandalorian season three itself is planned to air in 2021.
Source:
TorrentFreak