Inclusion Criteria:

• Histologic documentation of B-cell NHL. All participants must have relapsed or refractory disease with no other approved therapies available that would be more appropriate in the investigator’s judgment
• Part 1 and Part 2 participants must have either evaluable or measurable disease as defined by the appropriate disease response criteria
• Have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2
• Hematologic laboratory parameters must meet the required criterias and the values must be without a transfusion or growth factors for at least 7 days prior to the first dose of study drug
• Participants of childbearing potential must have a negative highly sensitive serum pregnancy test (beta (β)-human chorionic gonadotropin) at screening and within 72 hours of the first dose of study treatment and must agree to further serum or urine pregnancy tests during the study.

Exclusion Criteria:

• Known active central nervous system involvement (CNS) or leptomeningeal involvement. CNS involvement may be allowed in specific cohorts as determined by the Study Evaluation Team (SET)
• Prior solid-organ transplantation
• Prior treatment with JNJ-80948543 and/or JNJ-75348780
• Chemotherapy, targeted therapy, or immunotherapy within 14 days before the first dose of study treatment
• Malignancy diagnosis other than the disease under study within 1 year prior to screening. Exceptions are squamous and basal cell carcinoma of the skin, carcinoma in situ of the cervix and any malignancy that is considered cured or has minimal risk of recurrence within 1 year of first dose of the study drugs in the opinion of both the investigator and sponsor’s medical monitor
• Autoimmune or inflammatory disease requiring systemic corticosteroids or other immunosuppressive agents within 1 year prior to first dose of study treatment
• Evidence of active viral, bacterial, or uncontrolled systemic fungal infection requiring systemic treatment within 7 days before the first dose of study treatment