The purpose of this study is to evaluate the safety，tolerability, pharmacokinetics, and preliminary efficacy of KC1086 in participants with advanced recurrent or metastatic solid tumors. The trial will be divided into two parts: dose-escalation phase and dose-expansion phase.

Inclusion Criteria:

1. Histologically or cytologically confirmed recurrent or metastatic solid tumors;
2. Patients who have failed standard or conventional treatment or for whom no standard treatment is available( definition of treatment failure: intolerable toxic and side effects, disease progression during treatment recurrence after treatment);
3. Participants with advanced recurrent, unresectable, and/or metastatic tumors must have evaluable or measurable lesions (according to RECIST 1.1)；
4. Eastern Cooperative Oncology Group performance status score of 0 or 1;
5. Life expectancy > 12 weeks;
6. Adequate bone marrow, renal, and hepatic function;
7. Patients should participate in the study voluntarily and sign informed consent.

Exclusion Criteria:

1. Any patient who is known to have untreated central nervous system (CNS) metastasis;
2. Other kinds of malignancies within 5 years;
3. Gastrointestinal abnormalities;
4. Cardiovascular and cerebrovascular diseases;
5. Involved in other clinical trials within 4 weeks before enrollment;
6. Prior anti-tumor therapies with radiotherapy, immunotherapy, operation within 4 weeks before enrollment;
7. Prior anti-tumor therapies with small molecule targeting drugs within 2weeks or 5 half-lives (whichever is longer) before enrollment; Prior anti-tumor therapies with chemotherapy within 3 weeks or 5 half-lives (whichever is longer) before enrollment;
8. Presence of unresolved toxicities from prior anti-tumor therapy, defined as having not resolved to NCI CTCAE 5.0 Grade 0 or 1;
9. Severe infection within 4 weeks prior to enrollment;
10. Uncontrolled massive ascites, pleural or pericardial effusion；
11. Known history of human immunodeficiency virus (HIV) infection or current chronic or active hepatitis B or C infection requiring treatment with antiviral therapy;
12. Prior therapies with KAT6 inhibitors
13. Pregnant or lactating women;
14. Female subjects of child-bearing potential and male subjects of reproductive capacity who do not agree to use contraceptive measures during the study and for 6 months after the end of the study.
15. Other patients are not eligible for enrollment assessed by investigators.