What do you think scientist expect to discover more species?

The main reasons are the following:

1. protect species still not described  

2. discover new sources of biodiversity  

Explanation:

Biodiversity can be defined as the variety of species in a given area/ecosystem. The loss of biodiversity due to the extinction of species or decline in the genetic diversity of the wild populations may potentially lead to a breakdown of the functioning of a given ecosystem. Therefore, the discovery of species still not described is fundamental in order to protect them and thus ensure the correct functioning of each ecosystem. Moreover, and since new species also represent new sources of biodiversity, they can potentially contain beneficial unknown compounds that can be used to develop new medicines for treating diseases and injuries.

answer; analogue situations

d they all are treatable but they never completely go away