After completing at least 60 months (FL participants) or at least 24 months (MZL participants) of assessments in this study since the initial axicabtagene ciloleucel infusion and after agreement by the Sponsor, participants will transition to a long-term follow-up (LTFU) study, KT-US-982-5968 where they will complete the remainder of the 15 year follow-up assessments.