The two appeared on a recent episode. The whole interview is good listen, but the section of note is in Kyrie talking about playing Jayson for years. They seem to have a great friendship (contrary to what some posters have picked up from the "eye test").
“I see the same thing in what me and [Tatum] talk about now. We’re six years apart. And I try to tell him, I’m like, look: ‘I’m a liason between all of this… Whatever you need me to do. I’ll get out your way once you get to that point [of greatness]. You go ahead. This is yours. You want it? Go take it.’ And I tell J as well: ‘Me and you in this, going for the guts and glory. When it’s all on the line? I know I need you right next to me. So let’s get this thing going.’ I have a different relationship with all of my teammates but specifically with him, how special he is.”
Full episode here: https://itunes.apple.com/us/podcast/kyrie-irving-jayson-tatum/id1452698284?i=1000431594735&mt=2
Quick write up: https://celticswire.usatoday.com/2019/03/14/kyrie-irving-reveals-jayson-tatum-at-heart-of-talk-with-lebron-james/
Kyrie's comments don't surprise me at all. Prior to the recent drama, I had always gotten the vibe that he wants to take on less responsibility towards the back end of his prime. An ideal scenario in Boston would allow him to hand the keys over to Jayson and Jaylen. This is obviously contingent upon the team becoming a perennial title contender.