Starfield Skills -> Combat Skills
Dueling is a skill in Starfield located in the Combat skill tree that improves melee weapon damage and makes the player less vulnerable to damage while wielding a melee weapon.
Dueling Skill Description
Considered by many to be a lost art, close attacks with a melee weapon can often be deadlier than ranged combat when carried out by a skilled practitioner.

Dueling Skill Ranks
Rank 1
Melee weapons do 25% more damage. Take 10% less damage while wielding a melee weapon.
Rank 2
Melee kills make you run 20% faster for 10 seconds.
Rank 3
Melee weapons do 50% more damage. Take 15% less damage while wielding a melee weapon.
Rank 4
Melee kills heal you for 10% of your health.