An Open-label, Dose Escalation Study to Investigate the Safety, Pharmacokinetics, Pharmacodynamics and Clinical Activity of GSK3326595 in Participants With Solid Tumors and Non-Hodgkin's Lymphoma

Inclusion criteria:

* Males and females greater than or equal to (\>=)18 years of age (at the time consent is obtained)
* Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1 or 2
* Diagnosis of non-resectable or metastatic solid malignancy (as defined in the protocol) or NHL
* Presence of evaluable disease
* Adequate organ function (as defined in the protocol)
* Reproductive criteria (as defined in the protocol).

Exclusion Criteria:

* Malignancy attributed to prior solid organ transplant
* Leptomeningeal disease, spinal cord compression, or brain metastases that require immediate central nervous system (CNS)-specific treatment in the opinion of the Investigator (for example \[e.g.\], for symptomatic disease)
* History of a second malignancy, excluding non-melanoma skin cell cancer within the last three years
* Evidence of severe or uncontrolled systemic diseases, or serious and/or pre-existing medical or other condition that could interfere with participant's safety, obtaining informed consent or compliance to the study procedures, in the opinion of the Investigator
* Any clinically significant gastrointestinal (GI) abnormalities that may alter absorption such as malabsorption syndrome or major resection of the stomach and/or bowels.
* Select cardiac abnormalities (as defined in the protocol)
* History of sensitivity to any of the study medications, or components thereof or a history of drug or other allergy that, in the opinion of the investigator or Medical Monitor, contraindicates their participation.
* History of optic nerve neuropathy or neuritis.