In Andean Spanish, the /s/ is never aspirated in the final position, that is, it's pronounced [s] and not [h]; this [s] is sometimes pronounced apical rather than laminal  (a trait characteristic of northern Spain)
As in all American dialects, Andean Spanish has seseo (traditional /θ/ merges with /s/). That is, casa ("house") and caza ("hunt") are homophones. However, in Cusco many speakers realize /s/ as [θ] in some words, particularly in once, doce, trece.Seseo is common to all of America, the Canary Islands, and several areas in southern Spain.
Especially in the Ecuadorian variant, coda /s/ is often voiced to [z] before a voiced consonant (including sonorants) or a before vowel. In the Peruvian variant, it is palatalized before /i/.
In Bolivia, Ecuador, and southern Peru, /ʎ/ and /ʝ/ do not merge (lack of yeísmo).
Often the vowels /e/ and /i/ or /o/ and /u/ are merged, due to the influence of the tri-vocal system of Quechua and Aymara.
In northwest Argentina and north Chile today it is possible to say that there is a certain fusion in the dialects of those respective countries, but noting that more dominant are the local dialects. The Andean dialect can be seen northeast with respect to the pronunciation and lexicon. While the Rioplatense dialect provides some of the pronunciation, a variety of modes and the Argentine dialect replaces the Andean use of "tú" as the second person singular familiar pronoun with "vos". It is very similar in Chile, except that they alternate between "tú" and "vos" as the singular familiar second-person pronoun, and additionally present modes of Chilean Spanish and some of Andean Spanish.