iOS experienced 4 yr planning to change platform BigDataorML

Question

I have been iOS developer for more than 3.8 year now planning to switch platfrom from ios to bigdata or Machine learning . is it good to change platform .Im bit confused because not getting good opening for ios in MNC so if i change my platfrom will i get any good MNC .

 

IF yes WHich should i prefer the most Bigdata or Machine learning