Diablo IV's Gift of the Tree event runs from September 23 through October 7, with bonus Gift of the Tree Caches for completing Grim Favors. Blizzard confirms the activity and dates in its official September 23 announcement.

The developer presents the event as a response to Hell's Legacy arriving later than promised. If you are choosing an activity for the reward window, Grim Favors are the one named in the offer.

A Diablo IV character fights enemies in a snowy area
Official Season of Hell’s Legacy gameplay imagery. Blizzard’s event notice promises bonus caches for completing Grim Favors.Blizzard Entertainment

Blizzard promotes extra XP and loot but does not state a numerical XP multiplier. The notice also leaves the exact closing hour and time zone unspecified, so do not assume October 7 means the end of that day in your region.

The bonus-cache event does not include a promise to replace individual items or crafting materials lost to bugs. Those recovery requests still need their own confirmed support response. For the announced event itself, complete Grim Favors within the September 23–October 7 window.