A live stream from last year has resurfaced on social media that seems to suggest that Insomniac Games is making a third game alongside Marvel's Spider-Man 2 and Marvel's Wolverine.
During the stream, Erin Eberhardt (Project Director) stated that they were in charge of an unannounced project at the studio, stating that:
"This is actually my first triple-A game project now, I'm the project director here on an unannounced project. I'm very excited to actually be making the games now."
Insomniac in June 2021 started hiring for what looked to be a game that either had multiplayer elements or was a multiplayer title that as of writing still hasn't been announced, so there's the potential that the project that Eberhardt is referring to could potentially be this multiplayer title, especially with Sony recently pushing more live-service games in their showcases and in their general strategy. With Marvel's Spider-Man 2 ramping up marketing, it's unlikely that whatever this unannounced title is will be revealed until next year at the earliest.