A Study of Tislelizumab in Combination With Investigational Agents in Participants With Head and Neck Squamous Cell Carcinoma

Inclusion Criteria:

• Participants with histologically or cytologically confirmed R/M HNSCC that isconsidered incurable by local therapies

1. The eligible primary tumor locations are oropharynx, oral cavity, hypopharynx,and larynx

2. Participants should not have had prior systemic therapy administered in the R/Msetting; systemic therapy which was completed prior to randomization/enrollmentif given as part of multimodal treatment for locally or locoregionally advanceddisease is allowed

• Participants must have positive PD-L1 expression (Combined Positive Score [CPS] ≥ 1)

• Have at least 1 measurable lesion as defined per RECIST v1.1

• Eastern Cooperative Oncology Group Performance Status of 0 or 1

• Adequate hematologic and organ function as indicated by specific laboratory valueswithin 7 days of first dose of study drug

• Willing to use a highly effective method of birth control for the duration of thestudy and for ≥ 120 days after the last dose of study drug(s)

Exclusion Criteria:

• Recurrent or metastatic carcinoma of the nasopharynx (any histology), squamous cellcarcinoma of unknown primary, squamous cell carcinoma that originated from the skinand salivary gland primary tumor or non-squamous histologies (eg, mucosal melanoma)

• Prior therapy with an anti-PD-1, anti-PD-L1, PD-L2, T-cell immunoglobulin and TIM-3,LAG-3, or any other antibody or drug specifically targeting T-cell costimulation orimmune checkpoint pathways

• Any active malignancy ≤ 2 years before randomization/enrollment except for thespecific cancer under investigation in this study, those with a negligible risk ofmetastasis or death, and any locally recurring cancer that has been treatedcuratively (eg, resected basal or squamous cell skin cancer, superficial bladdercancer, localized prostate cancer, and carcinoma in situ of the cervix or breast)

• History of interstitial lung disease, noninfectious pneumonitis, or uncontrolledlung diseases including pulmonary fibrosis, and acute lung diseases

• A history of severe hypersensitivity reactions to other monoclonal antibodies or hasexperienced a severe immune-mediated adverse event (imAE), an imAE that led totreatment discontinuation, or a cardiac or ocular imAE of any grade with priorimmunotherapy

Note: Other inclusion and exclusion criteria may apply