I haven't played in years but the core game doesn't seem to have changed much. They tweaked lots: textures, hit-boxes, spray patterns, rankings, game modes, grenade types, guns, etc., but if you play a ranked match it will still be a 5 vs 5 bomb defusal.

The (sellable) lootboxes give you weapon skins. This is cosmetic, but the temptation to express yourself or flex with pretty guns is tempting.