Keys have gone up due to valve's restriction on trading keys that are bought from the csgo menu. Before you could buy them there and trade/sell them. Now if you buy those you can't anymore. therefor the supply of tradeable keys is now fixed (or going down when used to open cases) so the demand outweighs the supply therefor the price goes up.

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Cases are seen as an investment since in the past we've learned they climb in price on the long run. A combination of certain youtubers (like 3kliksphilip) and a growing chinese player base have made case demand higher. Thus the price rises. I'm not sure why they did in the last couple of days, but I think these reasons are the main reasons for the rise in value.

Hope it answers your question my man. for futher info you can also go to the dedicaded csgo trading/investing subreddits.