Summary
- Star Trek: Section 31 could explore the mystery of the Chameloids' absence during DS9 Dominion War, shedding light on their loyalties.
- Detroiters co-creator Sam Richardson will play a Chameloid in the movie, suggesting a relationship with Section 31.
- Section 31 may have retained Chameloids as intelligence operatives, withholding information from Federation for their benefit.
Detroiters co-creator and star Sam Richardson's role in the DS9's Dominion War, raising the question of where the Chameloid's loyalties lay.

Changeling Vs. Chameloid: Star Trek’s Shapeshifters Differences Explained
What's the difference between DS9's Changelings and Star Trek's earlier shapeshifting aliens, the Chameloids?
Chameloids Were Nowhere To Be Seen In Star Trek: DS9’s Dominion War - But Why?
Given how the Changeling threat impacted the civil liberties of people living on Earth during Star Trek: Deep Space Nine's season 4 two parter, "Homefront/Paradise Lost", it's strange that the rights of other shapeshifters never came up. There's a solid production reason for this oversight, as DS9's writers would have been keen to avoid confusion by introducing a different race of chameleonic aliens. Still, the in-universe explanation for the Chameloids' absence from the Dominion War never came. If they were allies of the Federation, the Chameloids would surely be a vital ally in the war against the Changelings.
...rounding up and imprisoning Chameloids to prevent them allying with the Changelings would be a normal day's work for Starfleet's shady intelligence organization.
Alternatively, if the Chameloids were enemies of the Federation, then there could be darker reasons for their absence from Deep Space Nine's Dominion War. Section 31's Dominion War crimes were extensive, and rounding up and imprisoning Chameloids to prevent them allying with the Changelings would be a normal day's work for Starfleet's shady intelligence organization. However, if a Chameloid was a former Section 31 asset or operative, then the organization may have looked on the shapeshifting species more favorably, offering them protection during the Dominion War.
Section 31 Can Finally Explain Chameloids 30 Years After Star Trek VI
Star Trek: Section 31 will explore the relationship between Sam Richardson's Chameloid character and the intelligence organization first introduced in Deep Space Nine. As all information about Section 31 and its operatives was erased at some point prior to DS9 season 6, episode 18, "Inquisition", it's possible that details about the Chameloids were also redacted. In Star Trek VI: The Undiscovered Country, Martia (Iman) assists the Khitomer conspirators with their plan to have Captain James T. Kirk (William Shatner) killed, which suggests an existing relationship between Section 31 and the Chameloids.
The Star Trek: Section 31 novel Cloak revealed that iral Cartwright (Brock Peters) was an operative, suggesting the organization played a role in Star Trek VI's Khitomer Conspiracy.
Perhaps Section 31 retained the services of the Chameloids and then withheld information about their existence from the wider Federation. Kirk refers to the Chameloids as "mythical" in Star Trek VI: The Undiscovered Country, implying that encounters have been incredibly rare. A near-mythical race of shapeshifters would make for excellent intelligence operatives, meaning Star Trek: Section 31 can finally reveal what covert activities the Chameloids were up to before they retreated back to their mythical status.