, if someone holds 1btc from 2015 till date, how many btc will the person will be holding currently base on current Bitcoin values
You’re funny. If someone held 1 BTC since 2015, it’s still the same 1 BTC today. When you say “hold,” that means he didn’t sell or rebuy along the way.
So I don’t really see the sense of the question. Maybe what you actually want to ask is what the price was in 2015 and how much that same Bitcoin would be worth now, including the profit.
I agree.
1 BTC is still one BTC, in 2015 or in our day and year

Or maybe OP just wants to see some figures, so let’s break it down.
Back in 2015, the price of Bitcoin was around $300. That same $300 is now worth about $115,000, which means the profit is already $114,700. That’s almost 400x the initial investment.
So now the real question is, do you think it’s time to stop HODLing and finally take profit?
What about you OP, would you sell at the current price?