A Phase I Study of ROSE12 Alone and in Combination With Other Anti-tumor Agents in Patients With Solid Tumors

* Age \>= 18 years at time of signing informed consent form (ICF) * Eastern Cooperative Oncology Group (ECOG) PS of 0 or 1 * Adequate hematologic and end-organ function * Life expectancy \>= 12 weeks * Patients with histologic documentation of locally advanced, or metastatic solid tumor * \[Dose-escalation Parts and Biopsy Parts\]Refractory or resistant to standard therapies or standard therapies are not available * \[Dose-escalation Parts and Expansion Part\] Patients with confirmed availability of fresh tumor or representative tumor specimens * \[Biopsy Parts\] Patients with accessible lesion(s) * \[Expansion Parts\] Patients with ICI (immune checkpoint inhibitor)-refractory 2L-3L NSCLC (non-small-cell lung cancer) and 3L+ CRC (colorectal cancer) Exclusion Criteria: * Clinically significant cardiovascular or liver disease * Treatment with investigational therapy and anti-cancer therapy within 28 days prior to initiation of study drug * Any history of an immune-mediated Grade 4 adverse event attributed to prior cancer immunotherapy (other than asymptomatic elevation of serum amylase or lipase). * All imAEs from prior cancer immunotherapy (other than endocrinopathy managed with replacement therapy, stable vitiligo or stable alopecia) that have not resolved completely to baseline. * Adverse events from prior anti-cancer therapy that have not resolved to Grade ≤ 1 except for alopecia, vitiligo, or endocrinopathy managed with replacement therapy * Primary central nervous system (CNS) malignancy, untreated CNS metastases requiring any anti-tumor treatment, or active CNS metastases * Uncontrolled tumor-related pain * Uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent drainage procedures * Active or history of clinically significant autoimmune disease * History of severe allergic, anaphylactic, or other hypersensitivity reactions to chimeric or humanized antibodies or fusion proteins. \[Expansion Part\] * Prior treatment with investigational product which has MoA of Treg depletion * Malignancies other than disease under study within 5 years prior to Cycle 1 Day 1