I Am Legend 2 is confirmed to be in development, and a decision to carry on the sci-fi horror story in relation to its retconned, alternate ending sets up an entirely different sequel narration than the original film. Over a decade ago, Will Smith starred in the Warner Bros. original adaptation of Richard Matheson's 1954 science fiction novel where he alone confronted the Darkseeker-ridden, post-apocalyptic world. Smith, as the disputable main protagonist Robert Neville, worked for a Darkseeker cure-all in his solitude until the truth about the maligned blood-sucking creatures, a woman and her child, and his own role in the new world rapidly collided.
https://screenrant.com/i-am-legend-alternate-ending-sequel-different-explained/