Study Investigating Safety, Tolerability, Pharmacokinetics (PK) and Antitumor Activities of Anti-PD-1 (Programmed Death-1) Monoclonal Antibody

Key Inclusion Criteria:

1. Participants must have histologically or cytologically confirmed advanced or metastatic tumors (unresectable), have had progression or intolerability since last standard anti-tumor treatment, or have no standard treatment or have refused standard therapy.
2. Participants must be able to provide archival tumor tissues (paraffin blocks or at least 10 unstained tumor specimen slides).
3. Participants must have at least one measurable lesion as defined per RECIST criterion version 1.1.
4. Participant must have adequate organ function.
5. Females are eligible to participate in the study if they are:

   a) Non-childbearing potential (that is, physiologically incapable of becoming pregnant) who:
   * Has had hysterectomy
   * Has had bilateral oophorectomy
   * Has had bilateral tubal ligation or are post-menopausal (total cessation of menses for ≥1 year) b) Childbearing potential:
   * Must be willing to use a highly effective method of birth control for the duration of the study, and for at least 120 days after the last dose of tislelizumab, and have a negative urine or serum pregnancy test within 7 days of the first dose of study drug.
6. Non-sterile males must be willing to use a highly effective method of birth control for the duration of the study.

Key Exclusion Criteria:

1. History of severe hypersensitivity reactions to other monoclonal antibodies (mAbs).
2. Prior malignancy active within the previous 2 years except for the tumor under investigation in this trial, cured or locally curable cancers, such as basal or squamous cell skin cancer, superficial bladder cancer or carcinoma in situ of the cervix or breast.
3. Prior therapies targeting PD-1 or PD-L1. Active brain or leptomeningeal metastases. Participants with brain metastases are permitted if they are asymptomatic, for example, diagnosed incidentally by brain imaging, or participants with previously treated brain metastases that are asymptomatic at screening, radiographically stable and not requiring steroid medications for at least 4 weeks prior to the first administration of study treatment.
4. Participants with active autoimmune diseases or history of autoimmune diseases or immunodeficiency that may relapse should be excluded. Participants with following diseases are allowed to be enrolled for further screening: type I diabetes, hypothyroidism managed with hormone replacement therapy only, skin diseases not requiring systemic treatment (such as vitiligo, psoriasis or alopecia), or diseases not expected to recur in the absence of external triggering factors.
5. Participants should be excluded if they have a condition requiring systemic treatment with either corticosteroids or other immunosuppressive medications within 14 days of study drug administration.
6. With uncontrollable pleural effusion, pericardial effusion or ascites requiring repeated drainage.
7. Use of any live or attenuated vaccines within 4 weeks (28 days) prior to initiation of study therapy.
8. Major surgical procedure (Grade 3 or 4) within the past 4 weeks (28 days) prior to study drug administration.
9. Prior allogeneic or solid organ transplantation.

NOTE: Other protocol-defined Inclusion/Exclusion criteria may apply.