Info from the link:

Originally released in 2011, this is a brand new version of the game that will come with various enhancements. This also brings all the DLC into a complete package from MATABOO, Creative Assembly, and SEGA. It will be priced at £34.99 / €39.99 / $39.99 and include a 75% discount for owners of the original until November 12th, and people who purchase the new edition get gifted the original too.

• An updated and improved Total War: SHOGUN 2 and all of the associated DLC, including both Rise and Fall of the Samurai.
• Improved visuals with updated lighting, shadows, textures and more.
• 1440p and 4K UI scaling.
• Modernised controls.
• Japanese and Chinese voice acting and full text localisation.
• 50 + newly playable minor factions.
• Integrated in-game mod support using Mod.io.
• 64bit upgrade.