You gain the following benefits.
When you use the Intuitive Motion benefit of your Mark of Passage feat, you can roll 1d6 instead of 1d4.
When you use the Magical Passage benefit of your Mark of Passage feat to cast Misty Step without a spell slot, you can also choose up to two willing creatures you can see within 30 feet of yourself before you teleport. Each target can then take a Reaction to also teleport up to 30 feet to an unoccupied space it can see.