Not just one. Each passage has its own notes, and they don't say the same thing.
The NIV Grace and Truth Study Bible, available with Bible Gateway Plus, on 2 Samuel 21:15–22:
21:15–22 These stories highlight the achievements of David’s mighty men and special forces. Many of them perform deeds that echo David’s own achievements. Great leaders always reproduce their best virtues in others. For instance, Abishai kills the Philistine giant Ishbi-Benob, and Sibbekai kills the giant Saph, just as David killed Goliath. Verse 19 asserts that Elhanan the son of Jair killed Goliath’s brother. First Chronicles 20:5 records Goliath’s brother’s name: Lahmi.
The same resource, on 1 Chronicles 20:1–8:
20:1–8 Chapter 20 reports the capture of Rabbah (vv. 1–3) and battles with the Philistines (vv. 4–8). The Chronicler’s account diverges from 1-2 Samuel at several points due to his retelling of the same history from a different vantage point and for different purposes (see Introduction to 1 Chronicles). But perhaps no divergence is quite so significant as the omission of David’s sin with Bathsheba in the present chapter (cf. 2Sa 11).
5. Read what each note adds.
