Can you redirect a spell targeting you to a planeswalker you control?

Prior to a rules update in 2020, a rule existed (formerly CR 306.7) that allowed players to redirect a spell or ability that targeted a player to a planeswalker that player controlled instead. That rule was completely removed from the Comprehensive Rules. It no longer exists in any form.

Today, if a spell or ability targets 'a player,' it must target a player. Planeswalkers are not players, and there is no general mechanism to substitute one for the other. CR 115.4 defines what a legal target is, and a planeswalker is only a legal target if the spell or ability specifically says it can target a planeswalker (or a permanent, or uses similar broad language).

Some older planeswalker cards were issued errata to have 'damage that would be dealt to you' wording updated, but the blanket redirection rule itself is gone. If you want a planeswalker to 'absorb' a spell, you need an effect that specifically allows it — there is no default redirect anymore.

Example: Your opponent casts Lightning Bolt targeting you. You control Chandra, Torch of Defiance. You cannot choose to redirect that Bolt to Chandra. The Bolt resolves, dealing 3 damage to you. Chandra is unaffected unless another card or ability specifically redirects the damage or changes the target.

Reference: The planeswalker redirection rule (old CR 306.7) was removed effective with the Core Set 2021 rules update (July 2020). See also CR 115.4 on legal targets and CR 306 for current planeswalker rules, none of which contain a redirection provision.