One D&D will be compatible with D&D Fifth Edition, so if you have a pile of physical sourcebooks sitting in your library, or prefer 5E to the continuing adjustments made to the game through One D&D, you and your, first of all, should know that

You can sign up for the Unearthed Arcana playtest materials if you are excited about One D&D. The new One D&D core rulebooks won't be available until at least 2024 because new playtesting content should be dropping monthly.

One D&D focuses on diversity in all sorts of manners, which began in the sourcebook Tasha's Cauldron of Everything. The character creation in Unearthed Arcana no longer ties ability score bonuses to race, but links them to Backgrounds where your character has lived prior to the adventure you're beginning. It will be possible to make a custom background at least for now. This adds for more individualized character creation and story telling.