Steering back to the topic at hand.
With Kane's apparent health issues, the only way I could see Toronto trading for him would be a ratcheting series of conditional picks, similar to how Chicago acquired Timonen back in 2015.
(The below is not a value judgement, just an example)
Example:
Patrick Kane (50% Retained)
Alexander Kerfoot +
1 of the following
Toronto's 2023 2nd round pick
OR
Toronto's 2024 1st round pick (if Kane plays more than 4 games in the playoffs)
OR
Toronto's 2023 1st round pick (if Kane plays more than 8 games in the playoffs)
OR
Toronto's 2023 1st and 2024 2nd round pick (if Toronto makes the 2023 Cup Final)