Sensitive skin is usually genetic in nature and its effects can vary hugely by individual. Your skin may react to weather, pollution, certain product types / ingredients. Temporary sensitivity as a result of barrier disruption is known as sensitised skin - but the same approach applies regardless. Finding suitable products can be tough!
I advise fragrance / essential oil free products, and also keeping use of actives to a minimum. Overall, keep your routine simple and consistent, patch test all new products and introduce one new product at a time.