One Piece Chapter 1031
This was already made known to us before with Law looking for the Poneglyph and talking about wanting to find the meaning behind the Will of D... but to get confirmation in this way that he has a new dream (the same dream as Robin's) and that it still aligns perfectly with Luffy's gives me a lot of hope for Law sticking around in a big way, maybe even being with the Strawhats when they find Raftel.
(Now please just have the Polar Tang follow the Sunny for the rest of our journey and nip over every now and again for a cuppa tea and some Strawhat shenanigans)