These are the available variables possible to fetch to a GetAccept template from Teamtailor. Add these as custom merge field fields in GetAccept.
Job variables
tt.department
tt.role
tt.job.title
tt.job.stage
Recruiter variables
tt.recruiter.name
tt.recruiter.email
tt.recruiter.phone
Candidate variables
tt.first-name
tt.last-name
tt.email
tt.phone
Dynamic variables
tt.q.${question}
tt.cf.${api-name}