Study to Evaluate Safety and Clinical Activity of AB122 in Biomarker Selected Participants With Advanced Solid Tumors

Inclusion Criteria:

* Capable of giving signed informed consent.
* Male or female participants ≥ 18 years of age at the time of screening.
* Negative serum pregnancy test at screening and negative serum or urine pregnancy test every 3 months during the treatment period (women of childbearing potential only).
* Pathologically confirmed tumor that is metastatic, advanced, or recurrent with progression for which no alternative known to improve survival or curative therapy exists. Tumors must be TMB-H or Strata Immune Signature positive.
* Must have at least 1 measurable lesion per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1. The measurable lesion must be outside of a radiation field if the participant received prior radiation.
* Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1.
* Prior chemotherapy or certain immune therapies or biologic agents must have been completed at least 4 weeks (28 days) before investigational product administration and all AEs have either returned to baseline or stabilized.
* Previously treated brain or meningeal metastases with no evidence of progression by magnetic resonance imaging (MRI) for at least 4 weeks (28 days) prior to the first dose.
* Immunosuppressive doses of systemic medications, such as corticosteroids or absorbed topical corticosteroids (doses \> 10 mg/day prednisone or equivalent) must be discontinued at least 2 weeks (14 days) before investigational product administration. Physiologic doses of corticosteroids \< 10 mg/day of prednisone or its equivalent may be permitted
* Prior surgery that required general anesthesia or other major surgery as defined by the Investigator must be completed at least 4 weeks before investigational product administration
* Negative tests for hepatitis B surface antigen, hepatitis C virus antibody (or hepatitis C qualitative ribonucleic acid \[RNA; qualitative\]), and human immunodeficiency virus (HIV)-1 and HIV-2 antibody at screening
* Adequate organ and marrow function

Exclusion Criteria:

* Use of any live attenuated vaccines against infectious diseases within 4 weeks (28 days) of initiation of investigational product.
* Underlying medical conditions that, in the Investigator's or Sponsor's opinion, will make the administration of investigational product hazardous or obscure the interpretation of toxicity determination or Adverse events (AEs).
* History of myocardial infarction within 6 months or history of arterial thromboembolic event within 3 months of the first dose of investigational agent.
* Has known psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the trial.
* Is pregnant or breastfeeding or expecting to conceive or father children within the projected duration of the study, starting with the pre-screening or screening visit through 90 days after the last dose of investigational product.
* Any active or documented history of autoimmune disease or history of a syndrome that required systemic steroids or immunosuppressive medications.
* Any acute gastrointestinal symptoms at the time of screening or admission.
* Prior malignancy active within the previous year except for locally curable cancers that have been apparently cured.
* Prior treatment with an anti-PD-L1 or anti-PD-1 as monotherapy or in combination.
* Prior treatment with temozolomide.
* Use of other investigational drugs (drugs not marketed for any indication) within 28 days or at least 5 half-lives (whichever is longer) before investigational product administration.