Inclusion Criteria:
1. Signed written informed consent
2. Female or male patients, aged at least 18 years
3. Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1
4. Life expectancy of at least 3 months as assessed by the investigator
5. Patients with confirmed locally advanced, unresectable, or metastatic solid tumors who have been previously treated with SoC and are no longer eligible for other therapies
6. Patients who have been treated with an ICI treatment as monotherapy or in combination as SoC
7. Have recovered from previous treatment
8. At least 1 measurable lesion according to RECIST Version 1.1
9. Adequate hematological, hepatic, and renal functions
10. Negative blood pregnancy test at screening for women of childbearing potential
11. Highly effective contraception during the study period and for 6 months after the last study treatment administration for WOCBP, and for male patients who are sexually active with WOCBP. Highly effective contraception methods are defined as:
* Hormonal methods of contraception including combined oral contraceptive pills, vaginal ring, injectable, implants, intrauterine devices such as Mirena and nonhormonal intrauterine devices such as ParaGard for WOCBP patients or male patients' WOCBP partners
* Tubal ligation
* Vasectomy
In addition to highly effective contraception, participating male patients:
* Must use a condom during the study period and for 3 months after the last study treatment administration when engaging in any activity that allows for exposure to ejaculate
* Must refrain from donating sperm
12. Must agree to abstain from donating blood while taking study drug and for 3 months following discontinuation of study treatment
13. Able to understand the character and individual consequences of clinical trial
Exclusion Criteria:
1. Patients with central nervous system metastases and/or leptomeningeal carcinomatosis with some exceptions
2. Patients with active or a documented history of autoimmune disease, immune deficiency or syndrome that required systemic corticoids (except the allowed dose) or immunosuppressive medications
3. Patients who received a previous ICI like anti-PD(L)-1 or an agent directed to another stimulatory or co-inhibitory T-cell receptor and was discontinued from that treatment due to toxicity
4. Patients under chronic treatment with systemic corticosteroids or other immunosuppressive drugs for a period of at least 4 weeks and whose treatment was not stopped 2 weeks prior to the first study treatment, with exceptions. Steroids with no or minimal systemic effect (topical, inhalation) are allowed
5. Patients with history of or current interstitial lung disease or fibrosis, and patients with pneumonitis
6. Other active malignancy requiring active intervention
7. Patients with previous malignancies other than the target malignancy to be investigated in this trial, unless a complete remission was achieved and no additional therapy is required during the study period
8. Patient with any organ transplantation, including allogeneic stem cell transplantation
9. Known severe hypersensitivity reactions to monoclonal antibodies, any history of anaphylaxis, or uncontrolled asthma
10. Any known allergy or severe reaction to any component of anti-CTLA-4 or anti-PD(L)-1 drug product
11. Significant chronic or acute infections requiring systemic therapy including SARS-CoV-2 (COVID-19) PCR positive testing
12. Clinically significant active cardiovascular disease
13. Any other medical conditions or psychological disorders that would increase the safety risk to the patient or interfere with participation of the patient or the evaluation of the clinical study in the opinion of the investigator
14. Pregnant, breastfeeding, or expecting to conceive or father children within the projected duration of the trial
