This is a study of SGR-1505, an oral inhibitor of MALT1, in subjects with relapsed/refractory (R/R) B-cell lymphomas to evaluate the safety, pharmacokinetics (PK), pharmacodynamics (PD), maximum tolerated dose (MTD) or maximum administered dose (MAD) and/or recommended dose (RD) of SGR-1505. Exploratory cohorts will evaluate additional PK, PD, preliminary anti-tumor activity, and safety to establish the SGR-1505 RD. A planned amendment will evaluate SGR-1505 in combination with other anti-cancer agents, such as BTK and BCL-2 inhibitors, in patients with specific B-cell malignancies.