Inclusion Criteria:

• Men or women ≥18 years old.
• Histologically and/or cytologically confirmed recurrent or metastatic advanced solid tumors.
• Absence of available standard therapy, failure of standard therapy, or ineligibility for standard therapy.
• Survival expectation is ≥12 weeks.
• Adequate major organ function at screening; no blood transfusion or hematopoietic growth factor administration within 14 days prior to screening; and no significant abnormalities in hematology, coagulation profiles, or blood chemistry.
• Eastern Cooperative Oncology Group (ECOG) performance status 0 to 1.
• Presence of at least one measurable target lesion as defined by RECIST 1.1
• Participants are willing to provide tumor tissue samples.
• Participants of childbearing potential must be non-pregnant at screening. Male and female of childbearing potential must agree to use effective methods of contraception throughout the study.
• Participants must have demonstrated a full understanding of the study, voluntarily signed the informed consent form (ICF), and be willing and able to comply with all study procedures and required follow-up visits.

Exclusion Criteria:

• Allergic to HW221043 Tablet or its components.
• Has a treatment history of KIF18A inhibitor.
• Known presence of a recognizable hypermutated phenotype.
• Prior receipt of any unapproved investigational drug or therapy within 28 days before first dose.
• Inadequate washout from prior antitumor therapy.
• Use of any medication that may interfere with the safety conduct of the study within 14 days prior to the first dose (or within at least 5 half-lives of the agent, whichever is longer), or planned use of such medications during the study period.
• Continuous use of systemic corticosteroids within 4 weeks prior to the first dose.
• Live vaccination within 28 days prior to first dose or anticipated during the study.
• Major surgery within 28 days prior to the first dose of the investigational product.
• Major surgical procedure within 28 days prior to first dose.
• History of another active malignancy within 3 years prior to initiation of the investigational product.
• ≥ Grade 2 prior antitumor therapy-related toxicity per CTCAE v6.0 (except abnormalities deemed clinically insignificant).
• Tumor invasion into adjacent vital organs, major vessels, or central nervous system (CNS), or evidence of progressive brain metastases.
• Presence of severe underlying pulmonary disease, severe cardiac/cerebrovascular disease, or clinically significant QTc prolongation.
• Presence of an active infectious disease.
• Diagnosis of an autoimmune disease or presence of an immunodeficient state.
• Inability to swallow oral medications, or uncontrolled nausea, vomiting, diarrhea, or other gastrointestinal dysfunction likely to affect drug absorption.
• History of alcohol abuse or substance abuse.
• Women who are pregnant, breastfeeding, or planning to become pregnant/ breastfeeding during the study.
• Any condition that, in the judgment of the Investigator, would make the participant unsuitable for enrollment.