ISIS stands for International Secret Intelligence Service. On October 13, 2014, the creators decided to "merge" ISIS with the CIA for season 6 due to the acronym's incidental association with the jihadist group, the Islamic State of Iraq and Syria, which gained notoriety for its violent actions in the Middle East earlier that year.
The show's creator has admitted in interviews that the show doesn't have a realistic time period in which it's set. The geopolitical Cold War situation doesn't align with the technology being used or Woodhouse's age.
Prior to his death, Brett Bunsen (Neal Holman) had been shot at least eight times: at least four by Sterling Archer (H. Jon Benjamin) and several others by coworkers Lana and Cyril, actress Rona Thorne, and once by the FBI.
Amber Nash's character, Pam Poovey, has a full back tattoo which reads: "For the Angel of Death spread His wings on the Blast, and breathed in the face of the foes He passed; and the eyes of the Sleepers waxed deadly and chill, and their hearts but once heaved, and forever grew still!" This is the third stanza to the poem "The Destruction of Sennacherib" by Lord Byron (George Gordon), an 18th century English poet. The poem is a reference to a biblical passage (2nd Kings 18-19) of how God destroyed the Assyrian army before it could attack Jerusalem.
According to an article on Vulture.com, the characters' appearances are based on friends of the show creators, as well as actors, models and other people in the Atlanta area. The models would pose for several pictures, which would then be used as reference points for the animation.
Jeffrey Tambor voices Len Trexler, the rival of Malory Archer, who is voiced by Jessica Walter. In the critically acclaimed comedy Arrested Development (2003), Tambor and Walter played husband and wife, and, once again, were constantly at odds with each other.
Four actors from Archer were previously lead characters on Arrested Development. In addition to the Jeffrey Tambor tie-in, Judy Greer played Kitty, his very devoted assistant and now plays Cheryl, Malory's (Jessica Walter) less than devoted secretary, and David Cross, who played Tobias, voiced the character Noah in Season 3 of Archer.
Archer's butler Woodhouse's name is a reference to famed British writer P.G. Wodehouse, best known for his series of Jeeves and Wooster stories, about a superlative British butler and his rather dimwitted employer.
The trivia items below may give away important plot points.
Doctor Krieger is the son of a Nazi scientist and lived in Brazil until he was 15-years old. When his father was killed, Malory brought him to ISIS where it was later revealed that he was a genetically identical clone of Adolf Hitler. Recently Krieger has called his supposed genetic heritage into question, saying, "And by the way, if I was a clone of Adolf goddamn Hitler, wouldn't I look like Adolf goddamn Hitler?!"
Archer grew up believing that his father was a war hero named "John Fitzgerald Archer;" various events in season one suggest that his father may be Maj. Nikolai Jakov of the KGB, Len Trexler of rival spy agency ODIN, or band leader Buddy Rich (although Malory is pretty sure it's either Jakov or Trexler). She later mentions a fourth possibility in the 3rd season, and in Archer: Once Bitten (2013), an unknown man appears to Archer in a flashback, claiming to be his father, making a fifth possibility.