Beneficial Bond

You speak the incantation and touch a willing creature within range. Both the caster and the creature they are touching benefit from a single innate ability that either creature has (provided that they remain touching, and the caster maintains concentration on the spell). The effect that is shared cannot be a spell or spell-like effect.

Some examples include:
A Gnome can share their Dark Vision.
A Tiefling can share their Hellish Resistance.

Dragonborn cannot share their breath weapon. 
Drow cannot share their innate "Darkness" spell.