This episode serves as the Season 6 finale and uses the "Suicide Squad" title as a play on the DC Comics concept.
If you were looking for the specific Suicide Squad team in Arrow , they primarily appeared in earlier seasons:
: It highlights the strength of Oliver’s relationship with Felicity, as she is the one who eventually brings him back from his drug-induced stupor. Analysis of Brooklyn Nine-Nine S6E18: "Suicide Squad"
: Jake Peralta assembles a "Suicide Squad" of the precinct's past enemies— The Vulture, Madeline Wunch, and Keith "The Vulture" Pembroke —to take down Commissioner John Kelly and his illegal "Stingray" spying operation.
: Oliver is accidentally dosed with a high concentration of Vertigo by Councilman Collins. This causes him to suffer vivid, agonizing hallucinations that force him to confront his failures as a hero, mayor, and father.
: The narrative strips Oliver down to his "fundamentals." By the end of the episode, he decides to return to his Season 1 roots, choosing to operate solo without the support of Diggle or Felicity (Overwatch).
Often cited as one of the best episodes of Arrow's sixth season, "Fundamentals" serves as a psychological deep dive into Oliver Queen's psyche.
: The episode concludes with a series of betrayals, most notably Madeline Wunch outmaneuvering Kelly to become the acting commissioner, a move that provides a temporary win for the 99th precinct but sets up future conflict. The Actual "Suicide Squad" in the Arrowverse