It’s certainly a possibility that the lost colony of Roanoke assimilated with the Natives of the land. But there are also several other plausible theories about what happened to them.

• Another theory is that the settlers of Roanoke left a literal message of where they went: Croatoan. When appointed governor of Roanoke John White returned after a three year journey back to England, there was no trace of the colony besides the word “Croatoan” carved into a tree. Some historians posit that the settlers left this message because they traveled to Croatoan island (now known as Hatteras island) and either assimilated or were killed by Natives.
• The settlers of Roanoke could have also attempted to sail back to England on their own due to lack of supplies and died at sea. They may have also been killed by Spaniards who were making their way north from their settlements in Florida. Additionally, there’s a possibility that they succumbed to sickness, although there were no bones ever located on the site.
• New archeological evidence suggests that European settlers did move inland, though they cannot say for certain whether it was the colony of Roanoke or not. Interestingly, John White outlined two forts in invisible ink on a watercolor map he created of the colony. No evidence of the forts were found, but when the locations were examined, English pottery fragments were excavated. Some believe this to be proof of the settlers move and subsequent assimilation with Natives inland, but it hasn’t been ruled out that this pottery was not left behind from residents of Jamestown.
• The lost colony of Roanoke is one of the more interesting tidbits of the history of colonization, but the fact still remains that colonizers from England rarely treated Native Americans well, so the possibility of the settlers being killed by Natives is still quite high.
• I’d suggest watching this video about the Lost Colony of Roanoke. It explains several of the most prominent theories, along with being quite funny.

It is quite likely that at least some of the settlers were killed by the native islanders or by disease.

• In August 1587, a group of 115 English settlers landed on Roanoke Island, just off the coast of what is now North Carolina. The governor of the colony, John White, departed on a journey back to England to retrieve supplies, but ended up being caught in a three-year naval war with Spain. When he finally returned to Roanoke in 1590, the settlers were nowhere to be found.

• Whilst it is not impossible that the settlers moved to another area and assimilated with the natives elsewhere, it is likely that at least some of them died in some way.

• One theory for this is that they faced violence from the Native Americans. This is because two English groups had already visited Roanoke to explore the area. The second group, in particular, was driven out by the unsurprisingly hostile natives who claimed that they were using too many of the island’s resources. As such, when the third group arrived to set up a permanent colony, it is likely that the Native Americans were not so willing to let them stay around.

• Another theory for this is that the settlers were the victims of New World diseases which they had no immunity to.