Captain America: Civil War was the last we saw of Sharon Carter, however we now know that the character almost made another appearance in the Marvel Cinematic Universe in ABC's Agents of SHIELD. Though Carter's appearance in the film was fairly recent, it's unclear when or if the character will be seen again.
Emily VanCamp, who played the character in both Captain America: Winter Soldier and Captain America: Civil War, spoke with Deadline about the role at the Television Critics' Association while promoting her new Fox series, The Resident. VanCamp revealed that an appearance on Agents of SHIELD was discussed, but scheduling conflicts got in the way. At the time, VanCamp had been busy filming the ABC series Revenge, in which she played the lead character.
Revenge was cancelled after four seasons in 2015, which suggests that if VanCamp were to have portrayed Carter on Agents of SHIELD, it would have happened during season 1 or season 2. This was the same time period where other MCU characters were appearing frequently on the show, such as Lady Sif from Thor, Dr. List from Avengers: Age of Ultron, and the Howling Commandos from Captain America: First Avenger. Sharon Cater could have joined a number of other SHIELD agents from the films who have been featured in the series, including Maria Hill, Jasper Sitwell, and Nick Fury. Sharon's aunt, Peggy Carter was also on the show and was a co-founder of the organization.
We can only guess what role Sharon Carter could have had on the series. One possibility is that it could have touched on the connection between the two Carters, since Peggy was shown in flashbacks for season 2. Though fans of Captain America always knew that Sharon was related to Peggy, their relationship wasn't officially revealed until Peggy's funeral in Captain America: Civil War in 2016.
When asked if Sharon Carter would appear in Avengers: Infinity War, VanCamp made it clear that she was unaware of her involvement in any upcoming MCU movie:
With Marvel, they can give you a call the day before you shoot. You don’t know what’s going on with their movies because they’re very secretive.
Since Avengers: Infinity War may not feature Carter, could the character somehow pop up in the fifth season of Agents of SHIELD? Time will tell.
Season 5 of Agents of SHIELD is expected to air on ABC sometime in the beginning of 2018.