Four volunteers in USA will be put into Devon island to simulate Mars. This is second simulation. It takes 12 months of time.
https://www.nasa.gov/missions/analog-field-testing/chapea/nasa-announces-chapea-crew-for-year-long-mars-mission-simulation/
Inside the Devon island there will be a NASA made "Mars station" and they will stay inside because it is "dangerous to go outside" altough not really.
Through a series of Earth-based missions called CHAPEAU (Crew Health and Performance Exploration AnalogUe), NASA aims to evaluate certain human health and performance factors ahead of future Mars missions. The crew will undergo realistic resource limitations, equipment failures, communication delays, isolation and confinement, and other stressors, along with simulated high-tempo extravehicular activities.
These scenarios allow NASA to make informed trades between risks and interventions for long-duration exploration missions.