Books 1 and 2 in The New Earth Series by Devon C Ford.
Their plans to survive the end of humanity were meticulous. Thorough. Flawed.
They landed back on Earth hundreds of years after their expected return, and now the planet they once called home is unrecognisable. Warring tribes threaten their very survival, and members of Sierra team and Dr. David Anderson must work with their now-sentient AI to find a way to live peacefully with the survivors of the African facility.
But a greater threat than the power struggle between humans presses in on them, and they must choose sides to protect themselves from the terrifying plague sweeping over the continent during darkness.
They must find a way. They must survive The Swarm.