Assignments and transfers require immigration authorisation and generate obligations beyond the visa.
Categories. Intra-company transferees, specialty occupation workers, treaty-based categories, and short-term business visitor status, which does not permit productive work in most countries.
Lead times. Months in many jurisdictions, and start dates should not be committed before authorisation is reasonably assured.
Business visitor limits. Attending meetings and negotiating are generally permitted; performing services, providing training and hands-on work are generally not. The distinction is enforced and the consequences of getting it wrong include entry bans.
Posted worker rules in some regions requiring notification, a local representative, document retention and application of host-country pay and conditions.
Tax. Residence rules, treaty relief, tax equalisation policies, shadow payroll, and social security coordination through totalisation agreements to avoid double contributions.
Employment status during assignment. Whether the home contract is suspended or continues, which entity is the employer, and which law governs — set out in an assignment letter, since silence produces claims in both jurisdictions.
Right to work verification in the host country, and continuing obligations to monitor expiry dates.
Repatriation terms, and what happens if the assignment ends early.