With the release of patch 2.0, there are several new ghosts to be found. Two of them are in the story mission "The Black Garden" on Mars. Follow the quest marker until you get to some minotaurs guarding the big gate. Take them out and you can enter "The Black Garden".
❱ Ghost #1 - The Aftermath (00:03) The first ghost will be high up on the wall in front of you. Follow the jumps from the video and collect the first ghost "The Aftermath".
❱ Ghost #2 - Vision 81 (02:04) Jump back down and follow the story all the way until you get outside. Turn right and look for the huge structure. Use the platform nearby to get onto a ledge and find the second ghost "Vision 81" up there.