The IETF is listed as partner on the m3aawg page here: https://www.m3aawg.org/our-partners
Bron Gondwana is also the liaison manager from M3AAWG to IETF.
Main contact point (beyond the liaison manager) is the M3AAWG Executive Director (Amy Cadagin): https://www.m3aawg.org/leadership
Link to last IAB Open update: https://datatracker.ietf.org/meeting/125/materials/slides-125-iabopen-m3aawg-liaison-summary-00