Lennon returned to music in 1980 with Ono on the album "Double Fantasy". Co-produced by Jack Douglas, the album's songs primarily focus on the couple's relationship, emphasising their love for each other and their son, Sean, with some songs discussing Lennon's hiatus. Lennon was murdered outside his apartment in New York City three weeks after the album's release. In the years following his death, many previously unissued songs have seen release on other albums, including "Milk and Honey" (1984), "Menlove Ave." (1986), and "Anthology" (1998). In 2020, to celebrate what would have been Lennon's 80th birthday, Ono and his son Sean released the box set "Gimme Some Truth. The Ultimate Mixes", which contained newly remixed versions of 36 of Lennon's songs.