Key Inclusion Criteria:  Histologically or cytologically confirmed advanced solid tumors  Part A: Individuals with advanced solid tumors who have received, been intolerant to, or been ineligible for all treatment known to confer clinical benefit Part B: Individuals with select indications who have received, been intolerant to, or been ineligible for all treatment known to confer clinical benefit Part C: Individuals with advanced solid tumors who have received, been intolerant to, or been ineligible for all treatment known to confer clinical benefit or whose disease is indicated for pembrolizumab monotherapy Measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 Eastern Cooperative Oncology Group (ECOG) performance status 0, 1, or 2 Adequate organ function Male individuals and female individuals of childbearing potential who engage in heterosexual intercourse must agree to use methods of contraception  Tissue requirement:  Part A and Part C: Must provide pre-treatment adequate tumor tissue sample prior to enrolment Part B: Must have fresh pre-treatment and on-treatment biopsy for biomarker analysis  Key Exclusion Criteria:  Concurrent anticancer treatment Any anti-cancer therapy, whether investigational or approved, within protocol specified time prior to initiation of study including: immunotherapy or biologic therapy (< 28 days), chemotherapy (< 21 days), targeted small molecule therapy (< 14 days), 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 cell transplantation Concurrent active malignancy other than nonmelanoma skin cancer, carcinoma in situ of the cervix, or superficial bladder cancer after undergoing potentially curative therapy with no evidence of disease. Individuals with other previous malignancies are eligible if disease-free for > 2 years History of intolerance, hypersensitivity, or treatment discontinuation due to severe immune-related adverse events (irAEs) or any life-threatening hypersensitivity to prior immunotherapy History of autoimmune disease or active autoimmune disease requiring systemic treatment within 2 years History of pneumonitis, interstitial lung disease, or severe radiation pneumonitis Active and clinically relevant bacterial, fungal, or viral infection that is not controlled or requires IV antibiotics Active hepatitis B virus (HBV) and/or hepatitis C virus (HCV), and/or human immunodeficiency virus (HIV) Positive serum pregnancy test or breastfeeding female Live vaccines within 30 days prior to Cycle 1, Day 1 (vector vaccines and messenger RNA (mRNA) vaccines are allowed) Significant cardiovascular disease  Note: Other protocol defined Inclusion/Exclusion criteria may apply.