Chemotherapy With Pembrolizumab Continuation After Progression to PD-1/L1 Inhibitors

Inclusion Criteria:

1. Male /female participants who are at least 20 years of age on the day of signinginformed consent with histologically confirmed diagnosis of

2. Histologically confirmed non-small cell carcinoma

3. Have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1.Evaluation of ECOG is to be performed within 7 days prior to the date ofallocation/randomization.

4. Received one or two cytotoxic chemotherapy for advanced NSCLC including at least oneplatinum-doublet

5. Has received prior therapy with an anti-PD-1, anti-PD-L1 agents (monotherapy) andprogression to last PD-1/PD-L1 inhibitors. The last PD-1/PD-L1 inhibitor should beadministered 6 weeks before the study enrollment, and no other systemic therapy shouldbe done between the interval.

6. At least one measurable lesion Have measurable disease based on RECIST 1.1. Lesionssituated in a previously irradiated area are considered measurable if progression hasbeen demonstrated in such lesions.

7. Available data for PD-L1 IHC results (any of one tested by 22C3, SP263, or SP142)irrespective of expression level.

8. EGFR and ALK wild type

Exclusion Criteria:

1. A WOCBP who has a positive urine pregnancy test within 72 hours prior to [randomization/allocation] (see Appendix 3). If the urine test is positive or cannotbe confirmed as negative, a serum pregnancy test will be required.

2. Has received prior systemic anti-cancer therapy including investigational agentswithin 3 weeks [could consider shorter interval for kinase inhibitors or other shorthalf-life drugs] prior to [randomization /allocation]. Note: Participants must have recovered from all AEs due to previous therapies to ≤Grade 1 or baseline. Participants with ≤Grade 2 neuropathy may be eligible. Note: If participant received major surgery, they must have recovered adequately fromthe toxicity and/or complications from the intervention prior to starting studytreatment.

3. Has received prior radiotherapy within 2 weeks of start of study treatment.Participants must have recovered from all radiation-related toxicities, not requirecorticosteroids, and not have had radiation pneumonitis. A 1-week washout is permittedfor palliative radiation (≤2 weeks of radiotherapy) to non-CNS disease.

4. Has received a live vaccine within 30 days prior to the first dose of study drug.Examples of live vaccines include, but are not limited to, the following: measles,mumps, rubella, varicella/zoster (chicken pox), yellow fever, rabies, BacillusCalmette-Guérin (BCG), and typhoid vaccine. Seasonal influenza vaccines for injectionare generally killed virus vaccines and are allowed; however, intranasal influenzavaccines (eg, FluMist®) are live attenuated vaccines and are not allowed.

5. Is currently participating in or has participated in a study of an investigationalagent or has used an investigational device within 3 weeks prior to the first dose ofstudy treatment. Note: Participants who have entered the follow-up phase of an investigational studymay participate as long as it has been 4 weeks after the last dose of the previousinvestigational agent.

6. Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy (in dosing exceeding 10 mg daily of prednisone equivalent) or any other form ofimmunosuppressive therapy within 7 days prior to the first dose of study drug.

7. Has a known additional malignancy that is progressing or has required active treatmentwithin the past 2 years. Note: Participants with basal cell carcinoma of the skin,squamous cell carcinoma of the skin, well differentiated thyroid carcinoma, orcarcinoma in situ (e.g. breast carcinoma, cervical cancer in situ) that have undergonepotentially curative therapy are not excluded.

8. Has known active CNS metastases and/or carcinomatous meningitis. Participants withpreviously treated brain metastases may participate provided they are radiologicallystable, i.e. without evidence of progression for at least 4 weeks by repeat imaging (note that the repeat imaging should be performed during study screening), clinicallystable and without requirement of steroid treatment for at least 14 days prior tofirst dose of study treatment. Patients with oligo (≤5) brain metastasis with sizeless than 1cm can be enrolled without prior radiotherapy, if the tumors are regardedas asymptomatic and stable, based on follow-up brain MRIs checked intervals of atleast 3 months. However, all patients with previously non-irradiated brain metastasesshould have brain MRI checked within 4 weeks before starting administration of studydrugs.

9. Has severe hypersensitivity (≥Grade 3) to pembrolizumab and/or any PD-1/PD-L1inhibitors.

10. Has active autoimmune disease that has required systemic treatment in the past 2 years (i.e. with use of disease modifying agents, corticosteroids or immunosuppressivedrugs). Replacement therapy (eg., thyroxine, insulin, or physiologic corticosteroidreplacement therapy for adrenal or pituitary insufficiency, etc.) is not considered aform of systemic treatment.

11. Has a history of (non-infectious) pneumonitis that required steroids or has currentpneumonitis.

12. Has an active infection requiring systemic therapy.

13. Has a known history of Human Immunodeficiency Virus (HIV)

14. Has a known history of Hepatitis B (defined as Hepatitis B surface antigen [HBsAg]reactive) or known active Hepatitis C virus (defined as HCV RNA [qualitative] isdetected) infection.

15. Has a known history of active TB (Bacillus Tuberculosis).

16. Has a history or current evidence of any condition, therapy, or laboratory abnormalitythat might confound the results of the study, interfere with the subject'sparticipation for the full duration of the study, or is not in the best interest ofthe subject to participate, in the opinion of the treating investigator.

17. Has known psychiatric or substance abuse disorders that would interfere withcooperation with the requirements of the trial.