Cannot sync old worlds from iPad to Nintendo switch minecraft.

i know this is Apple and i'm talking about a video game but this is something about apple. so i have a iPad and it has minecraft and today i got minecraft for the switch. i really love mnecraft on switch now but when i tried syncing my old world on switch form my iPad, it would not work. i do have a new world on the switch that i'm gonna work on a lot but is there any suggestion for this problem?