The study was conducted to assess the safety and tolerability of (1) polyethylene glycol (PEG) PEGylated Recombinant Human Hyaluronidase (PEGPH20) in combination with cisplatin (CIS) and gemcitabine (GEM) (PEGCISGEM), and (2) PEGPH20 in combination with CIS, GEM, and atezolizumab (PEGCISGEMATEZO).