Pesach - Shir HaShirim on Pesach – Minhagim and the Chabad Approach - אמירת שיר השירם

From Rulings and insights from the Lubavitcher Rebbe - Rabbi Chaim Wolosow by R Chaim Wolosow.

Some communities recite Shir HaShirim on Shabbos Chol HaMoed Pesach, reflecting the love between Hashem and Knesses Yisrael. The Rebbe notes that minhag Chabad is not to say it formally, aside from a custom—like his father’s—to recite it on the Seder night. https://www.torahrecordings.com/shulchan_menachem/orach_chayim/245