A Letter And A Number Ain’t Much To Go On
BioWare released a rather terse hint about the new Mass Effect game they are working on. The 34 second trailer consists of a shadowed female figure in a long cloak and a familiar helmet walking down a corridor towards a blustery exterior. She briefly turns to look at the viewer, revealing a N7 printed on her armour then turns her back again while unholstering a pistol and continuing her saunter.
The hero of the last Mass Effect game lacked the N7 designation, along with a lot of other things. That is enough to suggest you might be back in familiar territory, possibly with familiar friends. There is an outside chance you could see Shepard again too, depending on how you chose to end ME3. Then again BioWare is unlikely to want to completely abandon Andromeda, regardless of the wishes of fans, so we could see an amalgamation of the two storylines.
There really isn’t much to go on, other than the fact that Mass Effect 5 Epsilon is indeed in the works.