Spoilers ahead for the Season 7 finale of Arrow, called "You Have Saved This City."
The Season 7 finale of Arrow was the end of an era in many ways, ranging from the departure of leading lady Emily Bett Rickards to the dissolution of Team Arrow to the return of The Monitor to collect on Oliver's promise from the "Elseworlds" crossover of December 2018. Oliver gave his word that he would do whatever necessary to save Barry and Kara in the coming crisis, and it seemed quite possible that Oliver would not survive the mission. The Season 7 finale may have confirmed his death.
The main action of "You Have Saved This City" seemed to wrap up by about the 45-minute mark, which is never a good sign in the Arrow-verse. When things are tied up too neatly and too happily with more than a few minutes left in a finale, then something bad is probably going to happen. Emiko died, Palmer Tech/Queen Consolidated was leveled, and Oliver and Felicity had targets on their backs thanks to plans Emiko had in place before her death.
Still, Oliver and Felicity were poised to go into hiding in the quaint safe house revealed in the flash-forward episode, and they enjoyed a sweet little happily-ever-after... for a time. Unfortunately, their joy at a quiet life with their baby daughter was short-lived because The Monitor arrived. Oliver simply said that he thought he'd have more time, but he didn't fight against going. He knew that this was something he had to do.
The Monitor said that he'd seen the ways the crisis will unfold, and he'd seen Oliver die. The scenes set in the present seemed to confirm suspicions that Oliver was going to give his life in fighting the good fight in "Crisis on Infinite Earths." Then, the flash-forwards went so far as to show Oliver's headstone, which listed him as "Hero of Star City" and "The Green Arrow" as well as beloved son, brother, husband, and father. Oliver is totally going to die, right?
Well, maybe not. Felicity let Mia and William believe that Oliver is dead, but she's keeping secrets of her own. Finally at peace with Mia and William's abilities to protect themselves and no longer needing her to watch over them, Felicity walked away and met with The Monitor. Although he warned her that there was no coming back from where he was taking her, she simply said that she'd been ready for this for a long time. All signs point toward Felicity reuniting with Oliver.
The Monitor opened a portal and took Felicity through it, presumably to Oliver. He technically never clarified if he was taking her to another Earth or another plane of existence or even the afterlife, so we can't say if Oliver is alive or dead. At this point, all we can say with any certainty is that Arrow really is going to end Oliver's journey as the Green Arrow of Star City following the end of Season 8.
Based on Felicity's ending, I hope that Arrow filmed some scenes with her to air in the "Crisis on Infinite Earths" crossover, in case Emily Bett Rickards can't or won't return. We'll have to wait and see. The eighth and final season of Arrow will run for only ten episodes and return in the 2019-2020 TV season. The Arrow-verse is losing Arrow, but at least it's getting battier!