Tough to say, we know so little about the plot of Infinite. Here's kinda the best summary I can give you:

The Forerunner trilogy is an absolute beast (and I mean that in the best way possible). Takes place 100,000 years ago. Reason I bring it up is because the 2nd book, Primordium, takes place on Zeta Halo, where Infinite is going to be. Hard to say what kind of connections there will be, but might be worth checking out (or at least reading a synopsis).

Bad Blood, while it is a sequel to the short novel New Blood, takes place right after Halo 5. It stars Buck, and picks up the story after the game and goes a little more into the Created threat and the new state of the galaxy.

Legacy of Onyx also takes place after Halo 5, I wouldn't call it essential, it's very "young adult"-ish, but it is also a post-Halo 5 book.

Point of Light it itself a sequel to Renegades, also takes place after Halo 5, and briefly features Zeta Halo.

Shadows of Reach is likely the most "essential" even though I get the sense that back SoR and Infinite will be able to be enjoyed on their own. Shadows of Reach follows Blue Team, post-Halo 5, as they have to return to planet Reach.

And lastly, there is a book that came out last week called Divine Wind. Literally picks up hours after Shadows of Reach, stars Veta Lopis and her team of Spartan IIIs. I can't speak too much to this one because I am only 150 pages in. But it definitely features the Banished, so there could be some ties to Infinite.

Hope that helps!