This is a Phase I open-label, multi-center study of zamzetoclax (formerly GS-9716) tested either as monotherapy or in combination with other anti-cancer agents in patients with advanced solid malignancies. Primary objectives are to define the maximum tolerated dose (MTD) or maximum administered dose of zamzetoclax, and characterize the safety and tolerability of zamzetoclax as monotherapy and in combination with anti-cancer therapies.