This is a multicenter, open-label, first-in-human study to evaluate the safety,efficacy, and PK/PD characteristics of SIM0508 as a single agent and in combination with olaparib in participants with locally advanced/metastatic solid tumors.

Inclusion Criteria:

1. Voluntary participation and signature of informed consent form.
2. Participants with histologically confirmed ovarian cancer, prostate cancer,breast cancer , or pancreatic cancer.
3. ECOG score of 0 or 1.
4. Expected survival ≥ 12 weeks.

Exclusion Criteria:

1. Active hepatitis B (HBsAg or HBcAb positive and HBV DNA≥1×104 copies/mL or≥2000 international unit [IU]/mL) or hepatitis C (HCV antibody positive and HCV RNA≥ULN) infection; participant with HBsAg positive or detective HBV-DNA at screening should receive antiviral treatment as per local practice during the study.
2. Known human immunodeficiency virus (HIV) infection or acquired immunodeficiency syndrome (AIDS).
3. Participants unable to swallow study drug and participants with gastrointestinal disorders likely to interfere with absorption of the study drug.
4. Toxicities from previous anticancer therapies have not resolved (e.g to ≤ Grade 1).
5. Pregnant or nursing (lactating) women; other women of childbearing potential, unless the blood pregnancy test within 7 days of first dose of study drug is negative, and participants agree to use highly effective contraceptive methods from signing of informed consent to 180 days after the last dose of SIM0508 or olaparib, whichever comes later.
6. Male partinipants with female partners of reproductive potential, unless they agree to use highly effective contraceptive methods from signing of informed consent to 180 days after the last dose of SIM0508 and 90 days after the last dose of olaparib, whichever comes later.