Skills With Different Abilities
Finding its origin within the Player's Handbook (p.145), this section of rules offers a wider range of options for players to use their proficiencies in combination with one or more of the six different main abilities.
• Same Proficiency, Different Ability
Normally, your proficiency in a skill appliues only to a specific kind of ability check. Prociency in Athletics, for example, usually applies to Strength checks. In some situations though, your proficiency might reasonably apply to a different kind of check. In such cases, the GM might ask for a check using an unusual combination of ability and skill, or you might ask your GM if you can apply a proficiency to a different check.
For example, if you have to swim from an offshore island to the mainland, your GM might call for a Constitution check to see if you have the stamina to make it that far. In this case, your GM might allow you to apply your proficiency in Athletics and ask for a Constitution (Athletics) check.
So if you're proficient in Athletics, you apply your proficiency bonus to the Constitution check just as you would normally do for a Strength (Athletics) check. Similarly, when your half-orc barbarian uses a display of raw strength to intimidate an enemy, your GM might ask for a Strength (Intimidation) check, even though Intimidation is normally associated with Charisma.
