Difference between PNL vs M2M

In kite api , when I retrieve positions , I receive two parameters , PNL and M2M.Both gives same profit/loss , what is the difference ?

@vishnux

PNL is the Net returns on the position; Profit and loss, it takes difference between buy avg and sell avg price

M2M is the Mark to market returns (computed based on the last close and the last traded price) , It takes the difference between previous days settlement price and LTP.