The trailer for the Cortana - whose redesign isn't liked by fans - the show will feature a host of alien creatures from the franchise.
Halo's trailer also hints that Hunters may make an appearance in the show. The trailer shows a humanoid female character apparently leading Lekgolo worms as they attack UNSC officers. She apparently wants humans to surrender to the Covenant, suggesting that she's in league with the alien forces. The appearance of the Lekgolo worms is interesting, though, as it hints at the possible inclusion of a much larger threat.
In the Halo games, Lekgolo worms predominantly appear as Hunters, large warrior entities that are a unique gestalt of the smaller Lekgolo. While the trailer seemingly features Lekgolo worms, they aren't forming a Hunter, and instead are constricting soldiers as individuals. The Halo trailer features a number of alien species, but it's bound not to have disclosed all of the tricks the show undoubtedly has up its figurative sleeves.
Still, the fact that the Lekgolo are seen attacking a number of UNSC officers is perhaps the biggest hint that the show will eventually feature Hunters. As the worms are seen to be at odds with humans, it's likely that the two species will eventually find themselves in combat against one another. In the games, the Lekgolo take on the form of Hunters to make them more formidable in combat, and this would certainly lend itself well to the Halo TV show's blend of live-action and cutting-edge special effects.
There is a chance that the show will opt not to use the Lekgolo worms in the same way as the games, however. The Halo TV show has already made changes to numerous characters' backstories, so it may be that the Lekgolo worms aren't seen forming Hunters in the show. Still, showing the distinctly inhuman Lekgolo taking on a massive humanoid shape would be equal parts horrifying and suitably epic for the Halo show, and to use the Lekgolo without allowing them to form a Hunter would certainly feel like a wasted opportunity.
Therefore, the most logical route for the Halo TV show to take would be to use the Lekgolo in the same manner as the source material. As there's already been backlash from fans regarding changes to Cortana, making further needless aesthetic changes would only serve to hurt the show's credibility with fans - and so far, reactions to the live-action Halo TV show have been good. Whether or not Hunters will appear in the Halo TV show remains to be seen, but as the Lekgolo appear in the trailer, it certainly seems likely.