Study of GS-1811 Given Alone or With Zimberelimab in Adults With Advanced Solid Tumors

Key Inclusion Criteria:

• Disease:

• Part A: Individuals with histologically or cytologically confirmed advancedsolid tumors who have received, been intolerant to, or been ineligible for alltreatment known to confer clinical benefit.

• Part B: Individuals with histologically or cytologically confirmed selectindications who have received, been intolerant to, or been ineligible for alltreatment known to confer clinical benefit.

• Part C: Individuals with histologically or cytologically confirmed advancedsolid tumors who have received, been intolerant to, or been ineligible for alltreatments known to confer clinical benefit or whose disease is indicated foranti- programmed cell death protein 1 or programmed cell death ligand 1 (PD-[L]1) monoclonal antibody monotherapy.

• Part D: Individuals with pathologically confirmed select advanced solid tumors.

• Part E: Individuals with pathologically confirmed select advanced solid tumors.Participants must have received, have been intolerant to, or have beenineligible for all treatment known to confer clinical benefit.

• Part F: Individuals with pathologically-confirmed select advanced solid tumors.Participants must have received, have been intolerant to, or have beenineligible for all treatments known to confer clinical benefit; or, forparticipants who will undergo combination therapy, have disease which isindicated for anti-PD-(L)1 mAb monotherapy.

• Measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1

• Eastern Cooperative Oncology Group (ECOG) performance status 0, 1, or 2 forindividuals in Parts A, B, and C, and 0 or 1 for individuals in Parts D, E, and F.

• Adequate organ function.

• Male individuals and female individuals of childbearing potential who engage inheterosexual intercourse must agree to use methods of contraception.

• Tissue requirement:

• Parts A, C, D, E and F: Must provide pre-treatment adequate tumor tissue sampleprior to enrollment.

• Part B and select participants in Parts C and F: Must have fresh pre-treatmentand on-treatment biopsies for biomarker analysis.

Key Exclusion Criteria:

• Concurrent anticancer treatment.

• Any anti-cancer therapy, whether investigational or approved, within protocolspecified time prior to initiation of study including: immunotherapy or biologictherapy (< 28 days), chemotherapy (< 21 days), targeted small molecule therapy (< 14days), hormonal therapy or other adjunctive therapy (< 14 days) or radiotherapy (< 21 days).

• Any prior CCR8 directed therapy.

• Prior allogeneic tissue/solid organ transplantation, including allogeneic stem celltransplantation. Exception: prior corneal transplant without requirement forsystemic immunosuppressive agents is allowed.

• Concurrent active malignancy other than nonmelanoma skin cancer, curatively resectedcarcinoma in situ, localized prostate cancer, or superficial bladder cancer afterundergoing potentially curative therapy with no evidence of disease. Individualswith other previous malignancies are eligible if disease-free for > 2 years.

• History of intolerance, hypersensitivity, or treatment discontinuation due to severeimmune-related adverse events (irAEs) on prior immunotherapy.

• History of autoimmune disease or active autoimmune disease requiring systemictreatment within 2 years.

• History of pneumonitis, interstitial lung disease, or severe radiation pneumonitis (excluding localized radiation pneumonitis).

• Active and clinically relevant bacterial, fungal, or viral infection that is notcontrolled or requires IV antibiotics.

• Active hepatitis B virus (HBV) and/or hepatitis C virus (HCV), and/or humanimmunodeficiency virus (HIV).

• Positive serum pregnancy test or breastfeeding female.

• Live vaccines within 30 days prior to first dose.

• Significant cardiovascular disease.

Note: Other protocol defined Inclusion/Exclusion criteria may apply.