From Halopedia, the Halo wiki
The Champions Bundle was the fourth and final major expansion for the Halo 4 multiplayer experience. Developed by 343 Industries in conjunction with Certain Affinity and Digital Extremes, the bundle includes three packs, the Bullseye Pack, the Infinity Armor Pack, and the Steel Skin Pack, and was released on August 20, 2013. The expansion includes 10 new achievements and 250 Gamerscore. Unlike the other map packs, the Champions Bundle was not a part of the War Games Map Pass, and was launched individually for 800 Microsoft Points. Each pack can be purchased separately at lower prices, however, purchasing the bundle as a whole will unlock exclusive content. On July 7, 2017, along with all other Halo 3, Halo 4, and Halo: Reach DLC map packs, the Champions Bundle was made free to those on Xbox Live.
The weapon skins and armor permutations available with the Champions Bundle were not included within the Halo 4 component of Halo: The Master Chief Collection at launch, though the two maps and Ricochet gametype were. The launch of Season 4: Reclaimer in November 2020 saw the inclusion of all armor and weapon skins from across the bundle's various components within the collection, with 343 Industries expressing interest in bringing the Bullseye Pack and Infinity Armor Pack permutations to the game as well. The Resistor Tactical Package is not presently included in The Master Chief Collection.
The Bullseye Pack is a DLC pack released for Halo 4. It is also available as a standalone purchase for 480 Microsoft Points. The pack includes:
Infinity Armor Pack
The Infinity Armor Pack is the first and last armor pack to be released for Halo 4. It is also available as a standalone purchase for 240 Microsoft Points. It includes three new MJOLNIR (GEN2) armor variants:
Steel Skin Pack
The Steel Skin Pack is the first and last skin pack to be released for Halo 4, containing 10 steampunk-style skins for UNSC, Covenant and Forerunner weapons. As with the other packs, it may also be purchased separately for 240 Microsoft Points. The pack includes the following skins:
The Champions Bundle itself comes with exclusive content that players will not obtain if they buy the packs separately:
The DLC comes with ten new achievements.
The DLC comes with five new medals for the Infinity mode.