u can look up threats or synergies on my other guides or ask me on my twitch channel (just dm me)
in general i would say , threats for tanky yi are enemy team compositions with no burst or with a lot of tankyness. then the blade of the ruined king playstyle with kraken/rageblade would be way better.
synrgises well with ur team, if they need a jungler who can engage and tank a bit. so yea basically go this build if u feel like u still wanna do damage on yi, but cant be too sqishy.
it always depends what u build on yi, pn how ur team and enemy team drafts.