In 343 Industries’s first-ever “Ask343” Q&A, the studio confirmed that Halo Infinite PvP and PvE will be balanced separately, a new “never-before-seen” weapon will be introduced, new & classic weapons to be added over time and loads more.

Source: N4G PC Halo infinite PvP & PvE to Be Balanced Separately, "Never-Before-Seen" Weapon to Be Introduced