The children of Thanos seem to have taken cues from from their father's closet in Avengers: Infinity War.
With a version of the Black Order having been brought to live-action life in Avengers: Infinity War, one of Thanos; children was designed to bear a resemblance similar to his in a previous appearance.
"I took a lot of Proxima's look from the comics," Marvel Studios artist Jerad Marantz says in the studios's Avengers: Infinity War art book. "it was an honor to be able to establish her design in the film. I played around with her black-and-white suit and broke up the panels. I reworked her armored arm to expose more of her costume to show that it ws clearly armor and not another Marvel mechanical arm. I designed the armor in ZBrish based on the armor Thanos was wearing in Guardians Of The Galaxy. I was able to get the design approved in the first pass. I also decided to incorporate armor on her opposite leg for balance."
In Guardians of the Galaxy, Thanos wore armor similar to that of the flashback sequence seen in Avengers: Infinity War and might sport again in Avengers 4. Proxima Midnight, however, is not expected to return for Avengers 4 given her fate at the hands of Black Widow, Okoye, and Scarlet Witch.
The character's appearance in Avengers: Infinity War featured a golden armored arm with some edges being curved off of her body and pointed. This is the aspect which was similar to Thanos' armor as he was sitting on his throne speaking to Ronin the Accuser in 2014's Guardians of the Galaxy movie.
Avengers: Infinity War and Ant-Man and the Wasp are now available as a digital download as well as on Blu-ray and DVD. Upcoming Marvel Cinematic Universemovies include Captain Marvel on March 8, 2019, Avengers 4 on May 3, 2019, and Spider-Man: Far From Home on July 5, 2019.