BAF_FRontier-1, A First-in-Human, Phase 1 Trial to Assess Safety, Tolerability, and Preliminary Efficacy of LY4152199, a B-cell Activation Factor Receptor (BAFF-R) T-Cell Engager Bispecific Antibody in Adult Participants With Previously Treated B-cell Malignancies

Inclusion Criteria: * Must have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. * Estimated life expectancy of greater than or equal to (≥)12 weeks as judged by the Investigator. * Participants with select tumor types must have measurable or assessable disease as defined below: * Must have at least 1 bi-dimensionally measurable lesion or in the absence of measurable lymphadenopathy, documentation of bone marrow involvement. * Must be able to comply with inpatient/outpatient treatment, laboratory monitoring, and required clinic visits for the duration of trial partic…