Samsung Galaxy S8, S8+ & Note 9 Will Not Get Android 10

Samsung is all set to roll out the Android 10 updates to its flagship and mid-range smartphones. However, unfortunately, Samsung flagship models announced in 2017 or before are not entitled to receive the update. The flagships were promised two major updates and since the release, they have received the Android Oreo and Android Pie updates.
Samsung Galaxy S8, Samsung Galaxy S8+ and Samsung Galaxy Note 8 were released in 2017 and came preloaded with Android 7 Nougat, which is why they have received the updates they were entitled too.

Samsung has released its initial Android 10 update rollout road map and it contains many countries including Israel, China, India, and the Philippines. The road map has unveiled that the Korean giant will be sending Android 10 updates to 40+ Galaxy smartphone models including flagships and mid-rangers. These devices will receive the update at the start of 2020.
Previously, Samsung prioritized the flagship models when it came to sending updates, however, since the Company revamped its mid-range series, it has added mid-range models to the list of relatively faster updates as well.
Smartphones set to unveil in 2020 including the Galaxy S11 series, Galaxy S10 Lite, and Galaxy A51 and A71 will come preloaded with Android 10.