https://wccftech.com/halo-infinite-can-be-played-in-third-person-view-with-this-pc-mod/

If you've ever been eager to look at Master Chief while playing a Halo game, the PC mod developed by Opulent Halo for Halo Infinite delivers just that.

According to PC Gamer, you'll first have to download the Infinite Runtime TagViewer tool from GitHub. Once you've extracted the files to a folder of your choice, download the All Campaign Weapons 3rd Person mod and move its files to the mods directory of TagViewer.