From Halopedia, the Halo wiki
Inferno (Italian for "Hell") is the first part of Dante's Divine Comedy. The poem was written in the early 14th century. It is an allegory telling of the journey of Dante through what is largely the medieval concept of Hell, guided by the Roman poet Virgil. In the poem, Hell is depicted as nine Circles of suffering located within the Earth. Allegorically, the Divine Comedy represents the journey of the soul towards God, with the Inferno describing the recognition and rejection of sin.
In the Halo universe
In Halo: Ghosts of Onyx, when seeing the portal structure to the shield world in Onyx's core room antechamber, Chief Petty Officer Mendez mentions that it "reminds [him] of Dante's Inferno." Halsey corrects him that "Dante's hell was a series of descending rings," but is interrupted as the floor shifts when the rings in the portal structure begin to close.
Halo 3: ODST has drawn some speculation that it was inspired by the poem. In it, the protagonist is guided through a metaphorical hell by Vergil, a subroutine of the city's Superintendent AI. Towards the end of the game, he descends to Sublevel 09 of the Data Center, where part of it has been frozen, similar to Cocytus, the frozen ninth level of hell. In addition, the in-game audio drama Sadie's Story is divided into nine "circles", whose themes seem to mirror the circles of Hell as depicted in Inferno.
In Halo: Glasslands, after having Dr. Catherine Halsey arrested and brought to Ivanoff research station, Admiral Margaret Parangosky asks Halsey if she is familiar with Inferno, to which she replies that she has read it a long time ago in English. Parangosky then notes that Halsey won't be familiar with the Italian word contrapasso, the meaning of which she specifies to be the punishment of souls in Hell in a way it resembles their sin. Parangosky then compares Halsey's current state to contrapasso, as she has been kidnapped, stripped of all her authority and declared dead in the eyes of most of the UNSC, mirroring what she did to the SPARTAN-II candidates.