We enjoyed singleplayer in Tomb Raider but didn’t feel multiplayer was as fun, but it looks like there won’t be any additions to the story campaign of the game anytime soon, if ever. In an AMA interview on Reddit, one of the things discussed by Karl Stewart, Global Brand Director for Tomb Raider, was DLCs for the game.
He mentions there’s plenty being done to improve the multiplayer experience, since this is the first time they’re doing it in Tomb Raider. However, it seems that they’re basically placing all their focus into multiplayer as Stewart mentioned “All of our DLC is based around the Multiplayer experience for now … At this time there are no plans for single player DLC”. Yup that means no new collectibles or places to explore in singleplayer, and no additional Secret Tomb side missions (a shame since those puzzle-solving venues were loads of fun and there were only an odd half a dozen of them in the game).