Bill and Lance, as well as a few new characters, will be coming back in a rebooted version of the original Contra in Contra Mobile, which is heading to mobile devices in China sometime this year. (Thanks MMOCulture!)
The reboot features remade versions of many of the stages from the original NES version of the game, as well as some enemies and stages from later entries in the series. The trailer also shows that the player can carry various familiar and new weaponry that they can swap between, although with ammo limits. There are also multiple playable characters, although it is unclear how they differ from each other at this time.
Contra Mobile will also have a PVP mode for players who wish to tangle with other soldiers. There is no news on whether it will release in other territories at this moment.