Tomorrow

Given that in the trailer her body is seen levitating, with invisible stands attached to her body, on the laboratory table, it is possible that she possesses DOOMS.
She comes from a place where babies are not born, but remain in the mother's womb. Whether she is referring to the chrysalis in which she was found or something else is not yet known.
Given her true identity, Tomorrow might've referred to the Beach, a place where the Ka of babies who died in their mother's wombs go. A similar circumstance happened to Lockne's child when it died inside Mama.
Tomorrow is a Taurus, or its equivalent in the post-Death Stranding world.
Had she been born at the intended date, Lou/Tomorrow would've been a Cancer, which is a sign often born by DOOMS sufferers.

Tomorrow is likely suffering from DOOMS, of an unspecified level, which allows her to use tar to both move and attack, that appears to be released from small circular orifices on her forearm and, probably, the sole of her feet. When she uses her abilities, a golden substance, probably chiralium, drips from her eyes, which disappears when the danger is over.
When she uses it to move, Tomorrow summons a pool of tar from her bare feet, which she then uses to move underground by diving. As she moves, splashes of tar appear on the ground, following the girl's path until she decides to resurface and attack. She can also decide to use the tar to slide on the ground without submerging herself. When she uses the tar to attack, touching enemies with her hands, it seems to deteriorate the attacked area, which is then weaker to subsequent hits.
Tomorrow demonstrates unparalleled agility with jumps, pirouettes and spins and this agility proves useful both in dodging enemy attacks and in wrapping them up and dragging them under the tar puddle she creates. With her powers, she's able to fight Higgs' robotic body on nearly-equal terms.
Due to her true identity, Tomorrow is a repatriate like Sam, and death is temporary for her.