The CW's Arrow series finale quietly killed off Felicity Smoak, Oliver Queen's love interest, in its final scene, leaving many Arrowverse fans confused. Emily Beck Rickards debuted as Felicity Smoak in Arrow season 2, and her time on the show saw her eventually become Oliver's wife, and one of the series' most important main characters. However, Felicity was absent for The CW's crossover event, "Crisis on Infinite Earths," as Rickards departed from Arrow after season 7. Arrow's series finale, "Fadeout," saw the lovers reunite in the year 2040, but with the dark implication that they were both in the afterlife.

https://screenrant.com/arrow-felicity-dead-monitor-afterlife-reason-why/