John Gill Commentary 1 Chronicles 7:15

"and Machir took a wife of Huppim and Shuppim, whose sister`s name was Maacah; and the name of the second was Zelophehad: and Zelophehad had daughters." — 1 Chronicles 7:15 (ASV)

And Machir took to wife the sister of Huppim and Shuppim,
whose sister's name was Maachah
He married into the tribe of Benjamin, a sister of the persons mentioned, (1 Chronicles 7:12) whose name was Maachah:

and the name of the second was Zelophehad ;
the second son of Manasseh, or of his posterity mentioned; for he was not his immediate son; for he was the son of Hepher, the son of Gilead, the son of Machir, the son of Manasseh, (Numbers 27:1)

and Zelophehad had daughters ;
but no sons, the names of his daughters are given, (Numbers 26:33) (27:1) (36:11) (Joshua 17:3) .