There is not a season 7 of Supergirl as of right now but the show Supergirl from CW’s Arrowverse has been renewed for season 6 after ending season 5 without a finale due to COVID-19. This will be the last show to premiere over the whole of 2021 because the actress for Supergirl, Melissa Benoist is pregnant. But like Arrow, the Arrowverse plans on following and going up to 8-9 seasons each show from here on so it is likely that after season 6 they will renew it once again for season 7 but most likely during that time we won’t be seeing Mon-El anymore because Mon-El’s actor Chris Wood is married to Melissa Benoist so one of them will need to stay home to watch the baby while the other goes and records, but it will most likely be Melissa filming most cause she is the shows icon hero Sup