Safety and Efficacy Study of Pemetrexed + Platinum Chemotherapy + Pembrolizumab (MK-3475) With or Without Lenvatinib (MK-7902/E7080) as First-line Intervention in Adults With Metastatic Nonsquamous Non-small Cell Lung Cancer (MK-7902-006/E7080-G000-315/LEAP-006)-China Extension Study

Inclusion Criteria: * Histologically or cytologically confirmed diagnosis of Stage IV (American Joint Committee on Cancer \[AJCC\], version 8 or current version) nonsquamous NSCLC. * Confirmation that Epidermal Growth Factor Receptor (EGFR), ALK Receptor Tyrosine Kinase (ALK), or ROS1 Receptor Tyrosine Kinase (ROS1)-directed therapy is not indicated as primary treatment (documentation of absence of tumor-activating EGFR mutations AND absence of ALK and ROS1 gene rearrangements OR presence of a Kirsten Rat Sarcoma (KRAS) gene mutation). * Have measurable disease based on RECIST 1.1. Note: Lesions that appear measurable, but are situated in a previously irradiated area, can be considered measurable (eligible for selection as target lesions) if they have shown documented growth since the completion of radiation. * Provided an evaluable archival tumor tissue sample or newly obtained core or excisional biopsy of a tumor lesion (that was not previously irradiated) for central PD-L1 testing. * Life expectancy of at least 3 months. * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 within 7 days prior to the first dose of study intervention but before randomization. * Male participants must agree to use contraception during the treatment period and for at least 120 days after the last dose of pembrolizumab and/or lenvatinib/matching placebo and up to 180 days after the last dose of chemotherapeutic agents. A male participant must also agree to the following: 1)…