Fairly standard interview process as follows:
Recruiter screen (15-30m) - Questions regarding resume, skills, what you're looking for and typical HR questions.
Assessment (up to 3 hrs. estimate 60m) - take home assessment via HackerRank in your language of choice, fairly straightforward implementation, nothing too advanced.
Technical interview (60m) - 1 or more SWE from travelers, follow-up to your assessment. More in-depth questions about your resume and projects you've worked on, some questions may be asked about your work, why you chose to implement things, but also questions based on the fundamentals of your specific language choice. i.e. how would you call an API, how would you get certain data from the call, etc.
Behavioral (60m) - A panel of managers and possible SWE team members. A mix of questions related to your resume as well as STAR type behavioral questions, come prepared with multiple scenarios you can talk about with how you've handled difficult situations with customers, co-workers, and work.
Overall it's nothing too intense, Travelers wants to get to know you and how you think. How you would be as a coworker and employee seems to have more weight than how skilled you are technically, so take the behavioral rounds seriously. It's possible you aren't offered the job you applied for but the manager liked you and passed your name around to other managers. Travelers is a big and therefore they don't move fast, you have to have patience in the process.