1. We are discussing the matter later.

Question

2. We will discuss the matter later.
3. We are gling to discuss the matter later.
4. We discuss the matter later.
==============================
Are they all the same in meaning? Any differences?

Answer 1

Even though the verbs are not all in the same tense, 1, 2, and 3 mean approximately the same thing (as long as you mean ‘going’ in 3).

4 is not used.

Answer 2

1. We are discussing the matter later.
2. We will discuss the matter later.
3. We are going to discuss the matter later.
4. We discuss the matter later.

Answer 3

Even though the verbs are not all in the same tense, 1, 2, and 3 mean approximately the same thing.

4 is not used.