Spider-Man is set to appear in the fourth Avengers movie in 2019. We don't know the name of said 'Avengers 4' but we do know Spidey will be there.
Tom Holland debuted as Peter Parker/Spider-Man in Captain America: Civil War and this year will star in Spider-Man Homecoming. He's set to appear in Avengers: Infinity War as well. But in an interview with THR, Producer Kevin Feige confirmed that Spider-Man will also be in Avengers 4.
When asked more about the character's future, he said, "That's as far as it goes for now."
Originally, Infinity War was supposed to be a Part 1 and 2 combo, seating 2 as 'Avengers 4'. But now, that's not the case and the public is unclear. It's rumored that Sony is looking to end the Marvel relationship after Homecoming 2, scheduled in 2019, but there's no such discussion being had in public earshot.
What we do know, however, is that Spider-Man will be there for Infinity War, which is set to have an enormous roster of super heroes.