Here is Every Appearance of Kang and Kodos in “The Simpsons-Treehouse of Horror I – XXX”
“Treehouse of Horror VI”

In season seven, Kang and Kodos make their return Earthbound. The aliens make their appearance during “Attack of the 50ft Eyesores”. The segment involves giant advertisement figures coming to life after Homer steals Lard Lad’s oversized doughnut. That same doughnut makes a massive trek across the landscape as it rolls past Kang and Kodos in the dessert. In this rendition, the duo is hitchhiking with a sign requesting a lift to “Earth Capital”. Also, there is a callback to the old TV sitcom Mork and Mindy, and another classic alien Mork from Ork, when using the quote “shazbot!”

“Treehouse of Horror VII”

Season eight’s “Treehouse of Horror” is arguably the most famous and recognizable appearance of Kang and Kodos. “Citizen Kang” came at the height of the 1996 US federal election campaign between Bob Dole and Bill Clinton. The plot involves our two favourite aliens abducting and disguising themselves as the presidential candidates. After Homer uncovers their devious plan, Americans still vote for Kang to be the leader – because “it’s a two-party system”. Subsequently, all of humanity is enslaved, and the episode ends on the dark note narrative of the American electoral system.

“Treehouse of Horror VIII”

The Simpsons staff have done their best to keep the tradition alive of Kang and Kodos appearing annually, despite sometimes being shoehorned in at the eleventh hour. In the case of “Treehouse of Horror VIII,” their cameo was nearly cut before producers were swayed to leave it in. The cameo is brief interrupting the first segment “The Homega Man”. When France takes offence from one of Mayor Quimby’s jokes, they decide to launch a bomb directly at Springfield. While this neutron bomb enters orbit, it nearly strikes Kang and Kodos’ ship. When they report the incident to Rigel 7, they are not treated seriously – a good indication that these two are not well respected at home.
“Treehouse of Horror IX”

The ninth instalment of “Treehouse of Horror” is one of the strangest inclusions of Kang and Kodos. “Starship Poopers” starts out with Maggie Simpson growing a fang and green tentacles. When the aliens are summoned to the house by the baby, Marge reveals that Kang is Maggie’s real father. To settle the dispute, the characters appear on The Jerry Springer Show. However, it results in the death of the audience, production crew, and Springer. Finally, Kang and Kodos threaten to kill every politician if they are not given the baby, which seems like a pretty good deal to the Simpsons family.

“Treehouse of Horror X”

Kang and Kodos get their dues when they open up “Treehouse of Horror X”. In a variety-style program, the two crack terrible jokes while receiving canned laughter from a laugh track. After, the show pans out to see the Simpsons watching the show as a collection of previous renditions from older “Treehouse” episodes. Maggie makes a reappearance as Kang’s daughter alien, including using Kang’s voice to silence Lisa when she questions aliens relevance to Halloween.
"There are also other characters that come and go (also owned by the Warner Bros. Discovery conglomerate media company)."
Huh. Is that just referring to other characters from the show itself, or is this implying that the new season is going to have cameos from other WBD IPs