Lynda Carter who played Wonder Woman in the 1970’s television series was returning to the DC Universe as the President of the United States in the second season of Supergirl. We now have the title and description of that particular episode, be warned the description does have a spoiler for the first episode of Season 2.
LYNDA CARTER (“WONDER WOMAN”) LANDS IN NATIONAL CITY AS PRESIDENT OLIVIA MARSDIN — An attack is made on the President (guest star Lynda Carter) as hot-button, alien vs. human rights issues heat up in National City. Supergirl (Melissa Benoist) and the DEO are assigned to protect the President and bring in the responsible party. Alex (Chyler Leigh) teams up with Detective Maggie Sawyer (Floriana Lima) to investigate the case while Kara searches for a recently escaped Mon-El (Chris Wood), who she fears may be the alien behind the assault. Rachel Talalay directed the episode written by Jessica Queller and Derek Simon (#203). Original airdate 10/24/2016.
Source: Supergirl TV