INCB050465 in Combination With Rituximab, Bendamustine and Rituximab, or Ibrutinib in Participants With Previously Treated B-Cell Lymphoma (CITADEL-112)

Inclusion Criteria:

* Men and women, aged 18 years or older on the day of signing the Informed Consent Form (ICF).
* Histologically confirmed indolent/aggressive DLBCL, FL, MZL, or MCL.
* Participants with DLBCL, MZL or MCL must have received at least 1 prior line of systemic therapy with documented progression or documented failure to achieve CR or PR after the most recent systemic treatment regimen.
* Participants with FL must have received at least 2 prior lines of systemic therapy with documented progression or documented failure to achieve CR or PR after the most recent systemic treatment regimen.
* Ineligible for stem cell transplant.
* Participants with DLBCL must have failed or refused stem cell transplantation or failed first-line salvage therapy if ineligible for transplantation.
* Must be willing to undergo an incisional or excisional lymph node or tissue biopsy or to provide a lymph node or tissue biopsy from the most recent available archival tissue.
* Life expectancy of \> 3 months.
* Eastern Cooperative Oncology Group (ECOG) performance status score of 0 to 2 (see Appendix D).
* Willingness to avoid pregnancy or fathering a child.
* Ability to comprehend and willingness to sign an ICF

Exclusion Criteria:

* Evidence of transformed non-Hodgkin lymphoma histologies (with the exception of FL).
* Histologically confirmed rare non-Hodgkin B-cell subtypes.
* History of or central nervous system lymphoma (either primary or metastatic) or leptomeningeal disease.
* Prior treatment with idelalisib, other selective PI3Kδ inhibitors, or a pan-PI3K inhibitor.
* For participants to be treated with bendamustine (Treatment B), prior treatment with bendamustine (within 12 months of the start of study treatment). Participants with prior bendamustine treatment (\> 12 months before the start of study treatment) are eligible if they meet the following criteria:

  * Did not discontinue because of tolerability concerns.
  * Achieved either partial response (PR) or complete response (CR) to the bendamustine regimen of at least 12 months in duration before relapse/progression.
  * Experienced progression following a regimen containing an alkylating agent.
* For participants to be treated with ibrutinib (Treatment C), prior treatment with a Bruton's tyrosine kinase (BTK) inhibitor.
* Allogeneic stem cell transplant within the last 6 months or autologous stem cell transplant within the last 3 months before the date of the first dose of study treatment.
* Active graft-versus-host disease following allogeneic transplant.
* Hepatitis B virus (HBV) or hepatitis C virus (HCV) infection.