Inclusion Criteria:  Histologically or cytologically confirmed, newly diagnosed unresectable stage III or metastatic (M1a) intrathoracic NSCLC without EGFR sensitizing mutation or ALK translocation Age ≥ 22 years Have a PD-L1 positive (TPS≥1%) tumor by local laboratory assessment Measurable disease by RECIST 1.1 ECOG performance status of 0 to 1 Have not received prior systemic treatments for NSCLC. Life expectancy of at least 3 months Able to operate the NovoTTF-200T system  Exclusion Criteria:  Has an extrathoracic metastasis (i.e. M component is M1b or M1c) Has an EGFR sensitizing mutation and/ or ALK translocation If Stage III, can be treated with curative intent with either surgical resection and/or chemoradiation Has received prior systemic anti-cancer therapy or prior radiotherapy for NSCLC (palliative radiotherapy is allowed) Being unable to operate the NovoTTF-200T device independently or with the help of a caregiver Pregnancy or breastfeeding Significant illnesses not associated with the primary disease Implanted electronic devices (e.g. pacemaker) in the upper torso