This study aims to compare treatment with imipenem/relebactam/cilastatin (IMI/REL) as a fixed-dose combination (FDC) with piperacillin/tazobactam (PIP/TAZ) FDC in participants with hospital-acquired and ventilator-associated bacterial pneumonia The primary hypothesis is that IMI/REL is non-inferior to PIP/TAZ in the incidence rate of all-cause mortality