You'll explore the Nether, which will contain its fair share of flames.
Mɪɴecraft Dungeᴏɴs ᴊᴜsᴛ ɢᴏt ᴇᴠᴇɴ ᴍᴏʀᴇ Mɪɴecraft dungeᴏɴs ɪɴ tʜᴇ ꜰᴏʀm ᴏꜰ Flaᴍᴇs ᴏꜰ tʜᴇ Netʜᴇr. It's a paid DLC pack ᴀɴd, ᴀs tʜᴇ naᴍᴇ impʟɪᴇs, ɪᴛ's sᴇᴛ ɪɴ tʜᴇ Netʜᴇr. Dᴏᴡɴ ʙᴇʟᴏᴡ ʏᴏᴜ'll gaɪɴ access ᴛᴏ sɪx mɪssiᴏɴs, ᴡʜɪᴄʜ ɪꜰ ᴀʟʟ ɢᴏes smoothly sʜᴏᴜʟᴅ net ʏᴏᴜ a bunch ᴏꜰ ɴᴇᴡ ᴡᴇapᴏɴs, gᴇᴀʀ ᴀɴd ᴀʀᴛɪꜰᴀᴄᴛs—ʙᴜᴛ ʏᴏᴜ'll ɴᴇᴇᴅ ᴛᴏ murder a bunch ᴏꜰ ɴᴇᴡ Netʜᴇr-tʜᴇᴍᴇd enemies ᴛᴏ ɢᴇᴛ thᴀᴛ loot.
That will set you back $6, but there's also a substantial free update rolling out alongside. These free additions are mostly tuned to keep you in the game, the biggest being Ancient Hunts. These are procedurally generated missions you'll gain access to in the endgame, which "weave in and out of the Nether and other familiar parts of the Overworld in action-packed, stitched together adventures." Naturally, these runs have a higher chance to reward with rarer items, but they're the only way to get gear in a new rarity tier called "Gilded".
Gilded items will only drop from Ancient mobs, which are basically superpowered versions of enemies you'll have encountered before. Ancient Hunts will also be the best place to get gold, a new currency accepted by a Piglin merchant specialising in Gilded wares.
There's a bit more on how the endgame is being tweaked in this blogpost. In the meantime, both the free update and Flames of the Nether are available now.