PFS is defined as time from randomization until first objective radiological progression per RECIST 1.1 as assessed by BICR, or death due to any cause (in the absence of progression).

These analyses will include participants with PD-L1 expressing tumors and all randomized participants.

Overall survival (OS) is defined as the time from randomization until the date of death due to any cause.

The analysis will include all randomized participants with PD-L1 expressing tumors.

OS is defined as the time from randomization until the date of death due to any cause.

These analyses will include participants with PD-L1 expressing tumors as randomized and all randomized participants.

OS is defined as the time from randomization until the date of death due to any cause.

The analysis will include all randomized participants.

PFS2 is defined as the time from randomization until the earliest of the progression event (following the initial investigator-assessed progression), after the start of the first subsequent therapy, or death from any cause, whichever occurs first. The date of the second progression will be recorded by the investigator in the eCRF and defined according to local standard clinical practice.

These analyses will include participants with PD-L1 expressing tumors as randomized and all randomized participants.

To investigate the immunogenicity of volrustomig.

Change from baseline of physical functioning as measured by scores on the Patient-Reported Outcomes Measurement Information System (PROMIS) Short Form v.20 - Physical Function 8c are reported on a T score metric (mean = 50 and SD = 10), with higher scores reflecting better physical functioning.

The analysis will include all randomized participants.

Change from baseline of Global Health Status/Quality of Life subscale scores as measured by the European Organization for Research and Treatment of Cancer (EORTC) Item Library 172 are transformed to a 0-100 range; a higher score represents higher quality of life.

The analysis will include all randomized participants.

Adverse Events as assessed by Common Terminology Criteria for Adverse Events (CTCAE).

The concentration of Volrustomig in serum will be determined. Area under the curve is the integral of the concentration-time curve. The AUC reflects the actual body exposure to drug after administration. The AUC is dependent on the rate of elimination of the drug from the body and the dose administered.

The concentration of Volrustomig in serum will be determined (Cmax will be derived).

The concentration of Volrustomig in serum will be determined (Tmax will be derived).