There will not be a fifth season for Legacies. The CW has opted not to renew The Originals spinoff from Julie Plec (The Vampire Diaries), Warner Bros. TV and CBS Studios.
Legacies was on the bubble, but had a slight edge due to its ties to one of the CW’s signature series, The Vampire Diaries, but ultimately CW decided not to go forward with another season. The June 16 Season 4 finale will now serve as the series finale.
Source: Deadline.
Also a nice little send off from Entertainment Weekly towards the end of the TVD era.
https://ew.com/tv/legacies-cancellation-vampire-diaries-universe-ending/