This phase I trial is trying to measure the dose of a new oral therapy (JNJ-67856633) as a possible treatment for people with B-Cell Non-Hodgkin Lymphoma or Chronic Lymphocytic Leukaemia, who have gotten worse or not responded to other treatmentsA Phase 1, First-in-Human, Open-Label Study of the Safety, Pharmacokinetics, and Pharmacodynamics of JNJ-67856633, an Inhibitor of MALT1, in Participants With NHL and CLL

Exclusion

• Known active central nervous system (CNS) involvement for dose escalation and specific expansion cohorts as determined by the study evaluation team (SET)
• Prior solid-organ transplantation
• Either of the following: a) Received an autologous stem cell transplant less than or equal to (<=)3 months before the first dose of study drug. b) Prior treatment with allogenic stem cell transplant <=6 months before the first dose of study drug, has evidence of graft versus host disease, or requires immunosuppressant therapy for graft versus host disease within the last 4 weeks
• History of malignancy (other than the disease under study in the cohort to which the participant is assigned) within 1 year prior to the first administration of study drug. Exceptions are squamous and basal cell carcinomas of the skin and carcinoma in situ of the cervix, or malignancy which in the opinion of the investigator, with concurrence with the sponsor's medical monitor, is considered cured with minimal risk of recurrence within 1 year before the first dose of study drug. Concomitant malignancies that are unlikely to progress and/or preclude evaluation of study endpoints may be allowed after discussion with the Study Responsible Physician
• Prior treatment with a mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) inhibitor