Do resee peanut butter cups have caffeine?

Yes. Reese's Peanut Butter Cups do have a very slight amount of caffeine in them.

For example:

100 grams of a Peanut Butter Cup will have 7.0 mg of caffeine.

1 ounce of a Peanut Butter Cup will have 2.0 mg of caffeine.

1 miniature Peanut Butter Cup will have .5 mg of caffeine.

1 package 0.6 oz 1 cup (17g) of Peanut Butter Cups will have 1.2 mg.

1 package 1.6 oz 2 cups (45g) of Peanut Butter Cups will have 3.2 mg.