Yep, running is obviously a lot more weight bearing than cycling. So if you’ve been off your feet for a while, just be aware that there will be an obvious transition back to that as leg muscles get used to taking up a bit more of the slack.
Also, cycling is very much more inclined to be not as constant as running in aerobic effort. Headwind v tailwind, uphill v downhill coasting. Very evident in HR profiles between the two modes of transport. So your longer runs will be a bit more tiring than the cycling efforts where you get to cruise intermittently.