A Study of Carboplatin-Paclitaxel/Nab-Paclitaxel Chemotherapy With or Without Pembrolizumab (MK-3475) in Adults With First Line Metastatic Squamous Non-small Cell Lung Cancer (MK-3475-407/KEYNOTE-407)-China Extension Study

Inclusion Criteria:

• Has a histologically or cytologically confirmed diagnosis of stage IV (M1a orM1b-American Joint Committee on Cancer [AJCC]) squamous NSCLC.

• Has measurable disease based on RECIST 1.1 as determined by the local siteinvestigator/radiology assessment.

• Has not received prior systemic treatment for metastatic NSCLC.

• Has provided tumor tissue from locations not radiated prior to biopsy.

• Has a life expectancy of at least 3 months.

• Has a performance status of 0 or 1 on the Eastern Cooperative Oncology Group (ECOG)Performance Status.

• Has adequate organ function.

• If female of childbearing potential, is willing to use an adequate method ofcontraception for the course of the study through 180 days after the last dose ofstudy treatment.

• If male with a female partner(s) of child-bearing potential, must agree to use anadequate method of contraception starting with the first dose of study treatmentthrough 95 days after the last dose of study treatment. Males with pregnant partnersmust agree to use a condom; no additional method of contraception is required forthe pregnant partner.

Exclusion Criteria:

• Has non-squamous histology NSCLC.

• Is currently participating and receiving study therapy or has participated in astudy of an investigational agent and received study therapy or used aninvestigational device within 4 weeks prior to administration of pembrolizumab.

• Before the first dose of study drug: a) Has received prior systemic cytotoxicchemotherapy for metastatic disease; b) Has received other targeted or biologicalantineoplastic therapy (e.g., erlotinib, crizotinib, cetuximab) for metastaticdisease; c) Has had major surgery (<3 weeks prior to first dose).

• Received radiation therapy to the lung that is >30 Gray (Gy) within 6 months of thefirst dose of study treatment.

• Completed palliative radiotherapy within 7 days of the first dose of studytreatment.

• Is expected to require any other form of antineoplastic therapy while on study.

• Has received a live-virus vaccination within 30 days of planned treatment start.

• Has a known history of prior malignancy except if the participant has undergonepotentially curative therapy with no evidence of that disease recurrence for 5 yearssince initiation of that therapy.

• Has known active central nervous system (CNS) metastases and/or carcinomatousmeningitis.

• Has pre-existing peripheral neuropathy that is ≥ Grade 2 by Common TerminologyCriteria for Adverse Events (CTCAE) Version 4 criteria.

• Previously had a severe hypersensitivity reaction to treatment with anothermonoclonal antibody.

• Has a known sensitivity to any component of carboplatin or paclitaxel ornab-paclitaxel.

• Has active autoimmune disease that has required systemic treatment in past 2 years.

• Is on chronic systemic steroids.

• Had prior treatment with any other anti-programmed cell death 1 (anti-PD-1), orprogrammed cell death ligand 1 (PD-L1) or PD-L2 agent or an antibody or a smallmolecule targeting other immuno-regulatory receptors or mechanisms.

• Has participated in any other pembrolizumab trial and has been treated withpembrolizumab.

• Has an active infection requiring therapy.

• Has known history of Human Immunodeficiency Virus (HIV).

• Has known active Hepatitis B virus (HBV) or Hepatitis C virus (HCV) infection.

• Is, at the time of providing documented informed consent, a regular user (including "recreational use") of any illicit drugs or has a recent history (within the lastyear) of substance abuse (including alcohol).

• Has interstitial lung disease or a history of pneumonitis that required oral orintravenous glucocorticoids to assist with management.