A Phase 1/2, Open-label, Multi-center Study of the Safety and Efficacy of Alomfilimab (KY1044) as Single Agent and in Combination With Anti-PD-L1 (Atezolizumab) in Adult Patients With Selected Advanced Malignancies

Inclusion Criteria: * Age ≥18 years (≥20 years in Taiwan) * Histologically documented advanced/metastatic malignancies * Phase 1 and Phase 2 participants with advanced/metastatic malignancies who have measurable disease (non-measurable disease is allowed only in Phase 1) as determined by RECIST 1.1 will be eligible if, according to the National Comprehensive Cancer Network (NCCN) guidelines, there are no available therapies known to confer a clinical benefit for their disease, or they have exhausted all such available options. Additionally, the following specific tumor indications will be enrolled: 1. Phase 1: Participants with advanced/metastatic malignancies, and preferred indications (non-small cell lung cancer (NSCLC), head and neck squamous cell carcinoma (HNSCC), hepatocellular carcinoma (HCC), melanoma, cervical, esophageal, gastric, renal, pancreatic, and triple negative breast cancer) 2. Phase 2 Alomfilimab single agent: Participants with advanced/metastatic malignancies in indications in which signs of anti-tumor activity (Complete Response (CR), Partial Response (PR) or durable stable disease (SD) with tumor shrinkage that does not qualify for PR) were seen during the dose escalation of Alomfilimab as single agent 3. Phase 2 Alomfilimab in combination with atezolizumab: Participants with advanced/metastatic malignancies in the selected indications below, and/or indications which have shown promising activity in Phase 1: * NSCLC (anti-PD-(L)1 therapy naïve and pre-treated between 1 and 2 prior lines of systemic therapy for advanced disease) * Gastric (anti-PD-(L)1 therapy naïve and pre-treated) * Recurrent and/or metastatic HNSCC (anti-PD-(L)1 therapy naïve and pre-treated between 1 and 2 prior lines of systemic therapy for advanced disease) * Esophageal (anti-PD-(L)1 therapy naïve and pre-treated) * Cervical (anti-PD-(L)1 therapy naïve and pre-treated) * Indications, in which signs of anti-tumor activity has been observed in Phase 1 with Alomfilimab in combination with atezolizumab * Prior therapy with anti-PD-(L)1 inhibitors is allowed provided any toxicity attributed to prior anti-PD-(L)1-directed therapy did not lead to discontinuation of therapy * Eastern Cooperative Oncology Group (ECOG) Performance Status 0-1 * Life expectancy longer than 12 weeks * Must have a site of disease amenable to biopsy, and be a candidate for tumor biopsy according to the treating institution's guidelines. Participants must be willing to undergo a new tumor biopsy at screening, and during therapy on the study Exclusion Criteria: * Presence of symptomatic central nervous system (CNS) metastases, or CNS metastases that require local CNS-directed therapy, or increasing doses of corticosteroids within the prior 2 weeks of first dose of study treatment * History of severe hypersensitivity reactions to other monoclonal antibodies and/or their excipients * Known presence of neutralizing anti-atezolizumab antibodies (for patients previously treated with atezolizumab) * Having out of range laboratory values: creatinine, bilirubin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), absolute neutrophil count (ANC), platelet count, hemoglobin * Impaired cardiac function or clinically significant cardiac disease, including any of the following: 1. Clinically significant and/or uncontrolled heart disease such as congestive heart failure requiring treatment (New York Heart Association \[NYHA\] Grade ≥2), uncontrolled hypertension or clinically significant arrhythmia 2. QTcF \>470 msec on screening (electrocardiogram) ECG using Fridericia's formula (QTcF) or congenital long QT syndrome 3. Acute myocardial infarction or unstable angina pectoris * Known human immunodeficiency virus (HIV), active hepatitis B virus (HBV) or active hepatitis C virus (HCV) infection * Malignant disease, other than that being treated in this study * Any medical condition that would, in the Investigator's judgment, prevent participation in the clinical study due to safety concerns, compliance with clinical study procedures or interpretation of study results * Active autoimmune disease or a documented history of autoimmune disease * Participants previously exposed to anti-PD-(L)1 treatment who are not adequately treated for skin rash or had no replacement therapy for endocrinopathies should be excluded * Participants with a history of drug-induced pneumonitis or current pneumonitis * Systemic steroid therapy or any immunosuppressive therapy. Topical, inhaled, nasal, and ophthalmic steroids are not prohibited * Use of live attenuated vaccines against infectious diseases within 4 weeks of the first dose of study treatment. SARS-CoV-2 vaccines authorized for use by the competent local regulatory health authorities for active immunization to prevent COVID 19 are allowed (unless the vaccine is live or live attenuated) and must be given in accordance with the prevailing immunization guidelines. * Anti-CTLA4, anti-PD-(L)1 treatment within 4 weeks of the first dose of study treatment * Pre-treatment with anti-CTLA4 antibodies in combination with any other antibody or drug specifically targeting T-cell co-stimulation or checkpoint pathway * Presence of Common Terminology Criteria for Adverse Events version 5 (CTCAE v5) ≥Grade 2 toxicity (except alopecia, peripheral neuropathy and ototoxicity, which are excluded if CTCAE v5 ≥Grade 3) due to prior cancer therapy * Radiotherapy within 2 weeks of the first dose of study treatment, except for palliative radiotherapy to a limited field, such as for the treatment of bone pain or a focally painful tumor mass. To allow evaluation for response to treatment, participants enrolled in the Phase 2 part must have remaining measurable disease that has not been irradiated * Pregnant or lactating women